what is a transfer case fluid

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Transfer Case Fluid: Why It Matters, When to Change, & How to Do It

We’ve always seen multiple fluids and oils designed for different purposes at automotive shops. But why are these fluids important, and everybody wants to get them? The transfer case produces considerable heat and friction like the engine and transmission. So, to ensure the transfer case functions appropriately, a specialized fluid (lubricant) known as transfer case fluid is a must-have. It prevents excessive wear and damage to the transfer case and should be changed regularly. It cools and greases these parts to prolong their lifespan. Read on to find out more about this fantastic lubricant.

How Does Transfer Case Fluid Work?

The transfer case is the vehicle component placed on the back of the transmission. It divides power between the front and rear wheels of a 4WD or AWD.

First, transfer case fluid coats the internal layer and provides a protective layer. This protective layer decreases friction produced by movement and physical contact. Eventually, enough lubricating draws heat away from the gears and preserves the life and performance of the car. At the same time, a new batch of lubricant then enters the transfer case. This helps clean the components and prevents any dirt and moisture from reaching them.

How Often Do I Need to Change the Fluid?

While the transfer case fluid is an important element for smooth driving, it is also essential to know how often your car will need it. Transfer case fluid doesn’t last a very long time. It easily gets contaminated by carbon buildup after cooling down and becomes less effective at cooling and greasing the components. Generally, manufacturers recommend different maintenance intervals based on the vehicle type and intended use. Checking it every 20,000 miles (32186.88 km) to 30,000 miles (48280.32 km) is a good approach. Moreover, some cars noticed elongated service life, up to 100,000 miles (160934.4 km), but that’s an exception.

Best Way to Replace the Transmission Fluid

Many trucks and SUVs already have enough space underneath, so you usually don’t need to lift them. But if there isn’t enough room for you to get underneath, make sure to check your vehicle’s jacking instructions. Here’s the method to change the fluid like an expert.

Step 1: Get Your Car Ready

Wait for your car to cool down for at least 2 hours before dealing with the fluid. Also, make sure to set the parking brakes and place a block behind the wheel. 

Step 2: Fluid Draining

Look for the fill plug to drain the fluid; it’s usually at the back of the vehicle near the transfer case. Take out both the fill and drain plugs, and let the fluid drain out for as long as you can to get the most out.

Step 3: Reinstalling the Drain Plug

Now, put the drain plug back in and leave the refill plug open. If you can’t reach the fill plug, you can use an extraction or filler syringe to get the job done.

Step 4: Refill the Transfer Case

Unfortunately, you can’t check how much fluid is in there. Just fill it up until it starts coming out, using a syringe or the fluid bottle.

Step 5: Cleaning

Now, put back the fluid fill plug. Wipe off any extra fluid from the transfer case and properly get rid of the used fluid. Some auto parts stores will take it from you and recycle it for free.

Step 6: Start the Vehicle

Start the car and allow it to rest for some time. This way, the new fluid will be distributed throughout the transfer case.

Step 7: Check for Any Leaks

After replacing the transfer case fluid, check for any leakage from the drain plug or filter. By chance, if you notice it, simply tighten the plug or change the gasket or filter.

Symptoms of Poor Transfer Case

The transfer case is expected to have a long lifespan, but it doesn’t always turn out that way. Here are some common symptoms of having a poor transfer case.

• The problem with gear shifting. 
• Grinding, growling, or humming noises come from underneath the vehicle.
• Greasy puddle formation directly under the transfer case’s location.
• The problem is staying in 4WD.
• 4WD Warning Light Illuminates.

Why is It Important to Service the Transmission Fluid?

The fluid in the transfer case keeps its parts lubricated. But if the fluid gets dirty, it can’t lubricate well and may lead to serious damage. If you hear strange sounds, see leaking fluid, have trouble shifting gears, or notice a burning smell, it’s time to see a mechanic and get the transfer case serviced. Otherwise, the transmission fluid’s ability to absorb heat to regulate temperature will diminish, and transmission will deteriorate.

Transmission fluid service will prevent transmission issues and keep the vehicle working optimally. This process removes old, worn transmission fluid and replaces it with new to maintain your car.

Types of Transfer Case Fluid

Transfer Case Fluid can be conventional or synthetic, depending on how they are made. Conventional fluid is extracted from crude oil refining, while synthetic, as the name suggests, comes from the laboratory. Most transfer cases are packed with an automatic transmission fluid (ATF); the other options can be thick gear oil or specialty lubricants. From these options, the question arises: what’s the best transfer case fluid? Well, engine oil is certainly not the best choice. A specific fluid that increases peak efficiency is recommended for a 4WD system of an off-roading truck.

Differential Fluid vs. Transmission Fluid | Transmission Case Fluid

You must have noticed the similarities between differential fluid, transfer case fluid, and transmission fluid. These act as cooling lubricants for vehicles. However, these lubricants are different. Differential fluid, also known as gear oil, is for vehicles with manual transmission, while transmission fluid works specifically with automatic transmission vehicles.

Transfer case fluid is usually brown, blue, green, or yellow. The differential fluid is blue/green, and the transmission fluid case is often a clear fluid with tones of red. The other difference is their lifespan. Although they require regular replacement, their lifespan differs from each other.

Transfer case fluid and transmission fluid need regular replacement. However, the two lubricants have different lifespans. It’s rare to replace both fluids at the same time.

Check out our comprehensive guide for transmission fluids.

Common Problems and Their Solutions

Few problems can arise with transfer cases, and fixing them on time can prevent severe damage – one common problem is leakage. If you notice any fuel leakage from the transmission, determine its source and take it to an auto shop. The other common problem is noise coming from the transmission case . It can be due to worn bearings. If you’re having issues with your transfer case, it’s better to get help from a reliable mechanic instead of trying to fix it yourself. 

How to Pick the Best Fluid for Transfer Case?

The ideal way to pick the best fluid for your transfer case depends on the vehicle manufacturer’s manual. You can get the information for ideal Transfer Case fluid by looking at the appendix. When you notice it is always working properly, there’s no doubt you have used the proper fluid and maintained it.

A Lubricant That Every Vehicle Needs

When it comes to maintaining your car and extending its lifespan, we cannot neglect the fruitful outcome of selecting the right type of transfer case oil and changing it occasionally. Don’t damage your transfer case by not getting its fluid change. Whether you DIY it or take it to an expert mechanic shop, getting it changed is a part of the healthy maintenance routine. You can consult the owner’s manual or a qualified mechanic’s opinion on the type and frequency of transfer case oil changes to keep everything in order.

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Transfer Case Fluid: How Often & What Is It?

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If you aren’t familiar with the term transfer case fluid, do not fret. This article shall be taking you through some very intricate points that concern the transfer case and its fluid. And by the time we are through, you would be well-informed enough to make effective decisions.

A transfer case is a somewhat rectangular box that functions as a component of the drive train (a part of the vehicle that is not the engine but conveys power produced by the engine). It divides the power from the transmittance amongst all four wheels in your vehicle. The transfer case is not found in all vehicles; it is present only in multi-powered axle vehicles like all-wheel and four-wheel-drive vehicles that use both front and back axles.

Transfer cases are also called power take-off units (PTU), and these PTU’s come in different types: the 4WD low, transfer CA’s shift type, housing type, etc.

What is Transfer Case Fluid?

A transfer case refers to one of the components of the drive train in an all-wheel or four-wheel vehicle. As the name suggests, the transfer case is responsible for receiving power from the transmission and transferring it to the (front and rear) wheels, using the drive shafts. It also sends power to the transmission. Essentially, it harmonizes the front and rear wheels with the rotation between them.

The transfer case can be designed from gear or chain drive, so it can be driven by either of the two materials. Depending on the driver, you can convert the transfer case into either four-wheel or two-wheel mode, using the drive.

To control the transfer case, you need an electronic switch. Depending on the type of wheel, the transfer case may be selectable (as in a four-wheel-drive vehicle) or not selectable (as in an all-wheel-drive vehicle).

The power take-off unit fluids eliminate friction while also offering a cooling effect on the case and wet clutch. These functions carried out by the fluid ensure that the transfer case working efficiently with the clutch’s aid determines and send power as needed to the wheels. 

Transmission fluid could also be used in place of PTU fluid. Specialized transfer case fluids and thick gear oils could be used as transfer case fluids too.

Does My Car Need Transfer Case Fluid?

The question of whether the transfer case fluid is vital to the engine and the overall performance of the vehicle is a no-brainer. Whether as traditional gear oil or synthetic type, transfer case fluid is essential to some vehicles.

Transfer case fluid helps to remove heat from the transfer case and transmission, thereby reducing friction and lubricating the internal components in the transfer case. It also helps to keep the vehicle cool, allowing the gear to have a smooth turn, and stay in the desired position while engaging easily.

PTU fluid is needed where there is a PTU. So you should first identify whether your vehicle uses a transfer case or not. So, If your vehicle does have a transfer case, then the challenge is easy to resolve. 

Just as babies are helpless without their moms, so is your PTU useless without its transfer fluid because even if you attempt driving your car without a transfer case fluid, the case would only get thoroughly destroyed due to overheating and severe friction. Imminently your four-wheel drive would become the latest arrival in scrap town.

How to Replace Transfer Case Fluid?

As it is with many other things on the Earth, transfer case fluids are not eternal. The fluid would lose its lubricating abilities over time due to the breakdown of its composing chemicals. The fluid could also ‘vanish’ away if there is a shaft seal leak in the producing or consuming seals. 

The reason for this is that shaft seals are supposed to enclose the PTU fluids in normal conditions. Hence, it would be proper to check and observe the seals for evidence of damage before considering the PTU’s replacement. 

Some of the signs that follow a damaged seal include:

• A grinding noise from below the vehicle.
• The vehicle switches irregularly between two and four-wheel drives.
• Problems with changing gears.

After fixing the transmission seal problems, you can then proceed to replace the transfer case fluid. The process involved in replacing a transfer case fluid is easier than crushing on someone, we assure you. 

All you have to do is drain the excess fluid by uninstalling the drain plug. After draining is done, reinstall the plug and add the transmission fluid to the required level. You see, it’s easy. If your vehicle doesn’t have a drain plug because the case is completely sealed, suck out the fluid and replace it with a new one.

How Often Should You Change Transfer Case Fluid?

Two things you must ensure while using the transfer case fluid: it should not get contaminated or run low. If you allow this to happen, there is a chance that your vehicle will shudder and cause a failure of the differential.

If you want to prevent this to happen, make sure you replace the transfer case fluid periodically. It is recommended that you should change the fluid every 30,000 miles. This is especially important for tow trucks and four-wheel-drive vehicles. This is because these vehicles use the fluid and make it recycle more frequently.

Period change of transfer case fluid will help reduce the issues related to drivability. Do wait until you drive your vehicle up to 70,000 miles before you replace the transfer case fluid. The consequence of waiting includes inefficient engagement of the car’s drivetrain. This will lead to the overall poor performance of the vehicle.  

Final Thoughts

It’s easy to maintain a transfer case fluid. You either have to visit a mechanic to change the fluid regularly before the manufacturer’s stated service time interval or change the transfer fluid yourself. 

It would not be best to wait until the transfer case gets damaged before taking action as appropriate. 

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Transfer Case Fluid: How Often & What Is It?

Hello, my name is Henry. Here at Gear Sustain we recommend and review different products and services in the Automotive, Dirt Bike, and Motorcycle industries.

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What Fluids Can You Use for Your Transfer Case?

A transfer case is a necessary component of four-wheel drive and all-wheel drive vehicles. This gear system divides power between the front and rear axles to deliver optimal traction.

Transfer cases need fluid for lubrication. The fluid ensures the gears within the transfer case can move smoothly and dissipate heat. In return, the transfer case sustains less wear and shields the transmission from overheating. However, you must know what fluids you can use for your transfer case for the best performance. Continue reading below to find out your options.

Automatic Transmission Fluid

Many modern vehicles with transfer cases require automatic transmission fluid (ATF) for optimal performance. ATF is a specialized lubricant that withstands high temperatures, resists corrosion, and decreases the frequency of fluid changes.

ATF contains detergents and additives to prevent build-up and keep the transfer case clean. Its unique formulation ensures smooth operation and protects vital components from wear and tear.

Gear oil possesses a thicker consistency than ATF. This high-viscosity fluid can withstand high pressure and extreme temperatures. It’s ideal for heavy-duty vehicles and older automobiles. Gear oil is a durable protective layer that reduces friction and wear.

Gear oil includes additives that prevent oxidation and corrosion to maintain the performance and lifespan of the transfer case, safeguarding your vehicle's transmission system. Remember to check the vehicle's owner’s manual before adding gear oil to the transfer case.

Specialty Lubricants

Vehicle manufacturers develop specialty lubricants to meet the specifications of a vehicle's make and model. These lubricants offer optimal performance, provide superior lubrication, and ensure the smooth operation of the transfer case.

Specialty lubricants have additional benefits, such as enhanced thermal stability, improved wear protection, and extended fluid life. They can reduce noise and vibration to provide a smooth ride.

Note that these lubricants tend to be more expensive than standard ATF or gear oil. Despite the cost, the investment can be worthwhile for people seeking to optimize their vehicle's performance and lifespan.

Finding out what fluids you can use in your transfer case will also guide you in picking the proper transfer case parts when it’s time for repairs. Transparts Warehouse is the best resource for aftermarket transmission parts. Check out our products today!

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Home > DIY Repairs Transfer Case Fluid: What Is It and How To Change

Transfer Case Fluid: What Is It and How To Change

Jeffrey n. ross.

• September 20, 2021

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If Your Car, Truck, Or SUV Is Equipped With AWD or 4WD, Here’s What You Need To Know To Keep Your Transfer Case Properly Maintained.

Like all other aspects of a vehicle’s drivetrain system such as the engine, transmission, and axles, the transfer case (also referred to as a “t-case”) uses an internal fluid for proper lubrication. For proper vehicle maintenance, the transfer case fluid must be changed at regular intervals in order to keep your vehicle operating properly and to prevent excessive wear and/or damage to the transfer case that could lead to internal damage. 

If you own a car, truck, SUV, or van equipped with all-wheel drive or four-wheel drive, here’s what you need to know about the transfer case.

What Is The Transfer Case?

On vehicles equipped with four-wheel drive or all-wheel drive, the transfer case is the component that splits power between the front and rear wheels. The transfer case is mounted on the back of the transmission, and it uses driveshafts to send engine power to the front and rear axles. Different automakers suggest different transfer case fluid for their vehicles, so consult your owner’s manual when looking for the right type of fluid.

Some vehicles (like a Jeep Wrangler) have a manual transfer case with a lever that must be shifted by the driver in order to engage four-wheel drive. Newer vehicles (including the 2022 Jeep Wagoneer I recently drove) have an automatic transfer case that can be engaged either using automatic inputs such as sensors or driver-selectable push-button controls.

When Should You Change Transfer Case Fluid ?

Manufacturers tend to recommend different maintenance intervals based on the type of vehicle and intended use, but generally speaking, it’s safe to perform a transfer case fluid service every 30,000 miles. Vehicles that are used for towing or frequent off-roading should probably get this fluid changed more frequently.

Get the FIXD Sensor and free app today for a custom maintenance schedule based on your make, model, and mileage. Never miss important maintenance again with automated maintenance alerts!

Is This An Easy DIY Repair?

If you own a truck or SUV, changing the transfer case fluid is one of the easiest DIY jobs you could ask for, but some smaller AWD and 4WD vehicles can be a bit more challenging. Either way, this is an extremely easy job even for beginner-level DIYers since it generally only requires basic tools and a drain pan.

How To Change Transfer Case Fluid?

Knowing how to change transfer case fluid is very similar to the steps required to change manual transmission fluid . This service is basically just removing a threaded plug to drain out all of the old fluid and then removing the fill plug to be able to fill the transfer case back up.

Don’t damage your transfer case by forgetting to have the fluid changed. Whether you do it yourself or take it to a professional shop , this scheduled maintenance item should be a top priority to keep your vehicle on the road. 

Lifelong automotive enthusiast with a soft spot for offroading. Wrencher turned writer, but I still love to tinker on just about anything with an engine. Dream car: tie between a ‘71 Hemi ‘Cuda and a ’91 GMC Syclone. #GirlDad #SaveTheManuals

We’re here to help you simplify car care and save, so this post may contain affiliate links to help you do just that. If you click on a link and take action, we may earn a commission. However, the analysis and opinions expressed are our own.

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Transfer Case Fluid Exchange

Like an oil change for your 4X4’s transfer case, help optimize performance and longevity of this key component with a visit to Jiffy Lube ® for a transfer case fluid exchange.

WHAT WE DO:

Jiffy Lube ® drains and replaces it with transfer case fluid that meets or exceeds your manufacturer’s specifications.

HOW TRANSFER CASE FLUID EXCHANGE WORKS:

The transfer case is a gearbox found only in four-wheel drive and some all-wheel drive vehicles that sends drive power from the engine to the front axles. Lubricating fluid inside the transfer case draws heat away from the gears, helping to preserve the life and performance.

Your vehicle's transfer case fluid should be exchanged at your vehicle manufacturer’s recommendation.

Jiffy Lube ® recommends following manufacturer recommendations, where applicable, for maintenance schedules and service intervals.

Not all services are offered at each Jiffy Lube ® location. Please check with your local Jiffy Lube ® service center for specific services offered.

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Transfer Case Function, Fluid Level, & Condition

A transfer case is the center of the drivetrain of four-wheel drive and some all-wheel drive vehicles. Mounted to the back of the transmission, it splits engine power and sends it to the front and rear axles by means of front and rear drive shafts. It also synchronizes the difference in rotation of the front and rear wheels, and may contain one or more sets of low range gears for off-road use.

Low range gears in the transfer case allow the vehicle to drive at much slower speeds while still operating within the usable power band or RPM range of the engine. This also increases the torque available at the axles. Low-range gears are used during slow-speed or extreme off-road maneuvers, such as navigating dangerous roads, rock crawling, or when pulling a heavy load. This feature is often not present on all-wheel drive vehicles.

On some vehicles, such as four-wheel drive trucks or vehicles intended for off-road use, the transfer case is controlled by the driver. The driver can engage the transfer case into either two-wheel drive or four-wheel drive mode. This is sometimes accomplished by means of a shifter, similar to that in a manual transmission. On some vehicles, the transfer case may be electronically operated by a switch or button. Others have transfer cases that are not selectable and are permanently locked into all-wheel drive mode. This type of transfer case may also be called the center differential.

If you dissect a transfer case, you will find a few components that are common in all transfer cases, such as an input shaft. An input shaft is spun by the transmission and is connected to two output shafts: one that spins the front driveshaft, and one that spins the rear driveshaft. Most modern transfer cases also have a differential. The transfer case differential is just like the differential in the axles. It allows one output to spin at a different rate than the other to avoid driveline bind on hard surfaces.

The three basic types of transfer cases are part-time 4WD, full-time 4WD, and active 4WD.

Part-time 4WD is the most common type of transfer case. It allows you to operate the vehicle in two-wheel drive, four-wheel drive high-range (4Hi), and four-wheel drive low-range (4Lo). The 4Hi operation typically utilizes a differential to improve drivability. Part-time 4WD systems offer smoother operation on pavement and better fuel economy since the front driveshaft and axle can be cut off completely from the power. The strongest transfer cases are generally part-time systems because they are designed for real off-road use, often in truck and utility vehicle applications.

Full-time 4WD is the simplest type of transfer case. It sends power to the front and rear axles all the time. To eliminate, or at least diminish, driveline bind on hard surfaces, this type of transfer case also uses a differential in high range. Some offer a 4Hi lock position which locks the differential to improve traction on slippery surfaces, but will also cause binding when operated on dry pavement.

Active 4WD is the easiest type of transfer case to use because it does not require any input from the driver. A variety of full-time and part-time systems have been developed that use electronic, computerized, or mechanical means to adjust the amount of power delivered to the axles according to wheel slip. They have a variety of names and levels of performance, but they provide some of the benefits of a part-time system without the owner ever having to switch anything. Active 4WD was designed for smooth operation without any input from the driver and can be found on everything from trucks to luxury sports cars.

The primary difference between the transfer case in a 4WD vehicle and that of an AWD vehicle is that the latter does not offer an additional torque multiplying low gear ratio used for serious off-roading. In all wheel drive vehicles, there is a need to allow for driveline slip to avoid binding the driveline. This is accomplished by including differential gears inside the transfer case.

The transfer case is always working, whether you use the four-wheel drive on your vehicle or not. Your transfer case fluid level and condition should be inspected every time you get an oil change. Transfer cases may be filled with gear oil, automatic transmission fluid (ATF), or specialty lubricants. It is important to regularly inspect the transfer case for any damage, leaks, or other concerns. The fluid level and condition should also be inspected, as transfer case fluid may leak from the output shaft seals, input shaft seal, case gaskets, or fluid inspection and drain plug gaskets.

If you are considering purchasing a vehicle with a transfer case, have an ASE certified technician visually inspect the case exterior, the fluid level and condition, and test drive the vehicle to make sure the four-wheel or all-wheel drive system operates properly. Follow the vehicle manufacturer's recommendation regarding transfer case fluid type and how often it should be replaced. If the transfer case oil has become contaminated, shows evidence of metal particles, or is black in color, it should be replaced right away.

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How to Change Transfer Case Fluid: 4WD Guide

• January 25, 2024 January 16, 2024

Maintaining your four-wheel drive system is crucial for optimal performance, and one key aspect is changing the transfer case fluid. We’re here to guide you through this essential maintenance task. It’s simpler than you might think and can save you a trip to the mechanic.

Regularly swapping out your transfer case fluid not only protects your vehicle’s components but also ensures smooth operation when you’re tackling tough terrain. We’ll walk you through the steps so you can keep your 4WD system in top shape.

By taking care of your transfer case fluid, you’re looking out for your vehicle’s longevity. Let’s dive into the process and get your four-wheel drive ready for any adventure that comes your way.

Why is changing transfer case fluid important?

Maintaining our four-wheel drive systems is crucial, and one key aspect is changing the transfer case fluid. The transfer case is a vital component of any 4WD vehicle, responsible for transferring power from the engine to the front and rear axles. Over time, the fluid within this case breaks down, which can lead to several issues if not addressed.

Regularly replacing the transfer case fluid ensures that:

• Component Lifespan is Extended: Fresh fluid minimizes wear on the gears and bearings within the transfer case.
• Performance Remains Optimal: Proper lubrication guarantees the 4WD system operates smoothly, especially during challenging drives.
• Heat Buildup Is Reduced: Good fluid dissipates heat effectively, preventing overheating of the transfer case.
• Contaminants Are Removed: Old fluid can gather harmful particles that potentially damage internal parts. Changing the fluid flushes these out.

Undoubtedly, neglecting this maintenance task invites trouble. For instance, degraded fluid can become too thin to lubricate effectively or too thick to flow properly, hampering the transfer case’s ability to change gears seamlessly. Moreover, old fluid may foster corrosion within the transfer case, leading to expensive repairs down the road.

Awareness of the fluid’s condition is imperative as well, and we can monitor it by checking the fluid level and its appearance periodically. A dark, burnt-smelling fluid signals it’s time for a change. Here‚Äôs a snapshot of what we might observe if our transfer case fluid isn’t maintained:

Although it might seem daunting at first, changing the transfer case fluid is a task we can tackle with confidence. With the right tools and guidance, we’ll ensure our 4WD system remains reliable for any off-road adventure or demanding driving condition.

Tools and materials needed for changing transfer case fluid

Before diving into the transfer case fluid change, it’s essential to gather all the necessary tools and materials. Doing so ensures the process goes smoothly and prevents any mid-task hiccups.

Here’s a comprehensive list to help us get started:

• Socket set: To remove and tighten bolts.
• Torque wrench: For precise tightening of the transfer case drain and fill plugs.
• Fluid pump: A handy tool to easily add new fluid into the transfer case.
• Drain pan: To catch the old fluid without making a mess.
• Rags and cleaner: To clean up any spills and wipe down surfaces.
• Gloves: To protect our hands from chemicals.
• Safety glasses: To safeguard our eyes from potential splashes.

Selecting the proper fluid is paramount. Always consult the vehicle’s owner‚Äôs manual or service guide to determine the specific type and amount required. Here’s what we’ll need regarding materials:

• Approved transfer case fluid: Quantity and specification as per manufacturer recommendations.
• Replacement plugs and washers (if applicable): New hardware can ensure a proper seal and prevent leaks.

With these tools and materials at the ready, we’re well-equipped to tackle the fluid change. Keep in mind that while the process isn’t complicated, it does require attention to detail. We’ll need to follow specific steps, including safely raising the vehicle, locating the transfer case, properly draining the old fluid, and refilling with the new. And remember, if there’s any hesitation or uncertainty, it’s always best to consult with a professional or refer to a workshop manual for more detailed guidance.

Preparing your vehicle for fluid change

When tackling the task of changing the transfer case fluid in our 4WD vehicles, proper preparation is essential. We’ll cover the steps to ensure our car is ready for this maintenance procedure, ensuring a smooth and successful fluid change.

Safety First Before we dive in, we’ve got to talk about safety. Here’s what we need to double-check:

• Park the vehicle on a level surface to avoid accidental movement.
• Engage our vehicle’s parking brake to ensure it stays put.
• If we’re using jack stands, make sure they’re properly rated for our vehicle’s weight and securely placed.
• Disconnecting the battery can prevent any electrical mishaps.

Draining Process

To get our vehicle ready for the transfer case fluid change, we’ll need to set up for the actual draining of the old fluid. The specifics:

• Locate the transfer case drain and fill plugs before starting. They‚Äôre typically on the lower and upper side of the transfer case.
• Clean the area around the drain and fill plugs. This prevents debris from entering the case when the plugs are removed.

Essential Tools

For efficiency’s sake, let’s gather the tools we mentioned earlier:

• Torque wrench
• Rags and cleaner
• Safety glasses

By ensuring we have these items at hand, we’re all set to navigate the fluid change like pros.

The last thing we need to check is the specific type of fluid recommended by our vehicle’s manufacturer. Transfer case fluid types vary, and using the wrong one could lead to suboptimal performance or even damage. Interestingly, some modern vehicles use automatic transmission fluid, while others may call for specialized gear oils or synthetic fluids.

Fluid Level Check

Once we’ve taken care of the listed precautions, we’re ready to begin. It’s crucial to monitor the fluid level as we proceed with the maintenance routine. Maintaining the right level will keep our transfer case running effortlessly, which in turn ensures that our adventures off the beaten path are as exhilarating as they should be.

Steps to change transfer case fluid

Maintaining your vehicle’s four-wheel drive system is critical, and changing the transfer case fluid is a part of regular upkeep we can’t ignore. With the right tools and a bit of time, it’s a task we can handle ourselves. Here’s how we can go about it:

Firstly, gather all necessary tools and materials . We’ll need:

• A suitable catch pan to collect the old fluid
• A set of socket wrenches
• A torque wrench
• A new gasket or RTV sealant, if required
• The manufacturer-recommended transfer case fluid
• A funnel and a fluid pump for an easy refill

Once we have all that we need, let’s start the process:

Step 1: Draining the Old Fluid Find the transfer case drain plug, which is generally located at the lowest point. Place the catch pan under the plug, remove it with a socket wrench, and let the old fluid drain completely. It’s best to wait a few minutes to ensure all fluid has drained out.

Step 2: Replacing the Drain Plug If there’s a gasket, inspect and replace it if necessary before reinserting the drain plug. Use the torque wrench to tighten it to the manufacturer-specified torque.

Step 3: Refilling with New Fluid Locate the fill plug, remove it, and set it aside. Using a funnel and fluid pump, slowly add the new fluid. It’s the perfect time to ensure we’re using the exact type the manufacturer recommends. Fill it to the correct level, usually up to the bottom of the fill plug hole.

Step 4: Checking for Leaks With the new fluid in place, we should observe for any potential leaks. We also want to double-check that both drain and fill plugs are securely tightened to avoid any slipping or leaking.

To keep our 4WD system in peak condition, we’ll monitor the fluid level periodically, particularly after intense use or exposure to harsh conditions. Remember, this isn’t just maintenance‚Äîit’s about ensuring longevity and reliability for our vehicle’s performance on and off the road.

Signs your transfer case fluid needs to be changed

Maintaining your four-wheel-drive system is crucial for its longevity and performance. Understanding when to change the transfer case fluid can save us from future mechanical troubles. Here are some telltale signs to watch for:

• Difficulty Shifting Gears: If you’re experiencing hiccups while trying to shift between driving modes, it could be a sign that the transfer case fluid is either contaminated or at a low level.
• Unusual Noises: Should there be grinding, humming, or whining sounds coming from the transfer case area, it’s often an indication that the lubricating fluid has degraded; the need for a change is imminent.
• Leaking Fluid: Spotting a pool of fluid under your vehicle is a red flag. Transfer case fluid doesn’t burn off like oil, so if levels are low or you see a leak, it’s time for an inspection and likely a fluid change.
• Gear Slippage: This occurs when the gears can’t stay engaged. Gear slippage could very well be caused by inadequate or deteriorated transfer case fluid.

In diagnosing these issues, it’s paramount to ensure that they are related to the transfer case fluid and not other drivetrain components. Ruling out potential culprits is essential before proceeding with a fluid change. Regularly checking and maintaining the fluid level can assist in preventing these symptoms. However, once they present themselves, it’s typically a clear indicator that the vehicle requires immediate attention.

Regular maintenance schedules might not sync up with the actual wear and tear experienced by our vehicle’s transfer case. Factors like towing frequency, off-road usage, and climate conditions can influence the longevity of the transfer case fluid. Adherence to a more frequent maintenance timetable might be required to suit our specific driving conditions.

Knowing the health of our transfer case system allows us to tackle issues before they escalate. It’s not just about replacing fluids; it’s about ensuring our vehicle’s reliability when tackling different terrains or load conditions. Let’s keep an eye on these signs and act promptly to maintain the robust performance of our 4WD system.

We’ve armed you with the know-how to tackle transfer case fluid changes with confidence. Remember, regular maintenance is key to the longevity and performance of your 4WD system. By staying vigilant and addressing issues like gear slippage or unusual noises early, we can prevent more significant problems down the road. Trust in the process we’ve outlined and your vehicle’s manufacturer recommendations to keep your four-wheel drive running smoothly. Let’s ensure our adventures never end on account of preventable mechanical setbacks.

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diesel , duramax , transfer case , transfer case fluid

What is the best fluid to use in your transfer case.

If you’ve ever pulled your boat up a slippery ramp, run your truck through heavy snow or ice, or trucked right through deep mud on your rural property; then you have your truck’s transfer case to thank for getting you through the rough stuff! Yes, that hunk of metal under the cab of your HD truck houses a mechanism that seamlessly transitions power from the transmission to all 4 wheels of the truck (more on that later) so that you can maintain traction in a variety of challenging situations.

Of course, proper maintenance of your HD truck goes beyond just changing out the oil. The 4 - wheel drive system on these trucks is put under a considerable amount of stress and in order to properly maintain your 4 - wheel drive system, you’ll need to also keep up on changing out your fluid at regular intervals.

At Merchant Automotive, we get a TON of questions on what the best fluid solution is for GM trucks. Trust us, we’ve heard it all! We’ve caught wind of customers using everything from 5W-30 oil to universal ATF.

Sound confusing? Don’t worry, we’re here to set the record straight by covering everything you need to know about this unique component on your GM HD workhorse.

• How does a transfer case work?

What does good transfer case fluid do?

• What’s the best transfer case fluid?

If you’re interested in learning more about this critical component, we’re ready to pass on the knowledge!

How Does A Transfer Case Work?

The goal of your 4WD system is to allow the driver to operate the vehicle in either 2 wheel drive or 4 wheel drive, depending on the scenario that the driver finds themselves encountering, in a seamless manner. This is accomplished by engaging and disengaging the front axle of your truck via a clever component known as the transfer case, which you guessed it, transfers engine power to the front axle when called upon.

Engaging 4 wheel drive on your truck will give you optimal traction in slippery conditions but it will also use more fuel due to the power needed to move the additional drivetrain components and the additional wear/tear on those components. For example, if you’re pulling a trailer on a dry - highway for a long period of time, 2 wheel drive is optimal since the extra traction is not needed and fuel economy is the primary goal. Pulling your boat up a slippery ramp though? That’s going to require some extra traction.

The output shaft (from the transmission) powers the components in this component. Depending on either driver selection or computer engagement, power is either transferred directly to the rear axle OR shifted between the front and rear axle via a series of clutches, chains, and sprockets. This happens seamlessly and within fractions of a second.

The engagement or disengagement of the 4WD system is controlled right from the cab via a selector. This selector could be button-based or dial-based, depending on the year of your truck.

This is one of the coolest benefits of modern 4WD trucks. You can simply put your truck into AUTO and it will automatically engage 4WD as needed. It does this via a selection of wheel speed sensors that rotate in sync with the output shaft (towards the rear of the truck). Once there is a difference in rotational speed, the computer seamlessly engages a component that applies force to a series of clutches in order to equalize rotational speed. Boom. Traction!

This setting instructs your truck to ONLY engage the rear axle. Dry roads in the summer would be a good example.

This setting engages all 4 wheels at high speed (vehicle dependent but typically 50+) where traction may be an issue. For example, on a rain-soaked highway at high speeds.

This setting is for low speed ONLY and engages a separate set of gears that are specifically designed to multiply the torque of your engine when extremely tough situations are present. For example, when going through muddy terrain or when driving at slow speeds on ice or snow. This is for down-low grunt.

So, what’s this all got to do with utilizing the proper lubricant in your HD beast? Well, all these moving parts need proper lubrication to go the distance. A quality product needs to do three things:

• Lubricate the internal parts
• Address the specific needs of friction materials in the case
• Minimize driveline “clunk” or driveline friction.

You’ll hear all sorts of advice when it comes time to what kind of lubricant to put in your 2500 or 3500 HD truck.

Although it may only seem like lubricating oil, it does way more than simply keep things moving along smoothly. In fact, the factory actually fills the unit with a version of ATF known as Auto Trak II. That’s right! A version of the same stuff that’s in your Allison transmission is also in the 4WD system of your HD truck.

The reason behind this is due to the mechanical elements that are within the unit itself, including the usage of friction wet clutches inside of the unit. These wet clutches utilize a friction material (like all clutches do) and require way more than just engine oil to function properly. Basic engine oil (like a 10W-30) lacks the chemical properties required to properly cool, lubricate and maintain these friction materials, while ATF possesses the ability to properly lubricate these friction materials and lubricate the rest of the mechanical components as well.

Seems like a done deal, right? Not so fast.

What about that driveline clunk? This occurs when the friction on the spline of the main shaft and the slip yoke is sliding over the top of each other without proper lubrication as your truck comes to a stop. These components designed to do this but GM has never really offered a solid solution to stopping this annoying problem. In fact, drivers often come to us with this complaint and indicate an audible “clunk” that can be a bit unnerving. A properly lubricated spline will eliminate this situation.

What’s The Best Transfer Case Fluid?

Well, it’s certainly not engine oil! Hopefully, we’ve established by now that the 4WD system of your HD truck is a complicated piece of machinery that requires a specific type of fluid to operate at peak efficiency for the long haul. So, should simply use the ATF equivalent that’s specified from the factory? For GM, HD trucks, that would be Autotrak II and although Auto Trak II does cover 2 of the 3 items that are required in a great product, it doesn’t really address the driveline clunk that is so prominent on the trucks.

The solution? Merchant Automotive Performance Transfer Case Fluid.

We’ve designed this product to be a direct substitute for the factory fill and it blended specifically for use in GM trucks but it may be used in Ford, and Chrysler trucks as well. We’ve custom-blended this fully synthetic product to contain the right mixture of additives and modifiers to address the proper lubrication of internal components, address the friction components properly and reduce driveline “clunk” by properly lubricating the spline.

This product is a cost-effective alternative to the Auto Trak II that’s specified by GM and is suitable for both automatic and manual applications. Merchant Automotive has even conveniently sized this container at 2 quarts (the typical factory fill requirement) to prevent overfilling!

Application: Developed for ALL GM trucks that call for ATF or Auto Trak II for the fluid fill. May also be used in Chrysler, Dodge, Ram, and Ford trucks.

Models: GM 2500HD 3500HD Silverado & Sierra Trucks

Engines: 6.6L V8 Duramax diesel engines (LB7, LLY, LBZ, LMM, LML, L5P)

Years: 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020

Trust The Duramax and Allison Experts

For almost 2 decades, the Merchant Automotive team has been the authority in Duramax and Allison trucks. Our absolute expertise, in-house engineering team, and unique specialization allow us to offer products like our Merchant Automotive Performance Transfer Case Fluid that go above and beyond factory requirements for our valued customers. We could just settle for what everyone else recommends or recommend factory spec but that’s not what we do. Our commitment to innovation and our commitment to our customers ensure that our products will keep your truck on the road for the long haul. This is what we do! 

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What Is a Transfer Case?

In short, a transfer case is a part of a 4-wheel drive system that transmits the power from the engine to the front and rear axles of your vehicle. 

Transfer cases are also known as T-cases or Transfer boxes. 

What Is A Transfer Case And What Does It Do?

Generally, the transfer case can shift your 4WD vehicle from a 2-wheel drive system to a four-wheel drive system. It is a very critical part of the 4WD system.

In the case of 2-wheel drive vehicles, the engine power is distributed to the axles of the vehicle using a single prop shaft. However, for a four-wheel-drive vehicle, two different driveshafts are needed to transmit the power from the engine to all four wheels.

That’s when the transfer case comes to the scene because the transfer case is the spot where the connection between the rear and front axles, the driveshafts, and the engine takes place.

Simply put, the transfer case will accept the main drive shaft and then the driveshaft will be delivering the power from the engine to both the front and rear axles. Along with that, a transfer case is also necessary for attaining high and low torque transmission and aggressive traction off-road.

What Is The Function Of A Transfer Case?

In 4WD or AWD vehicles, the main function of the transfer case is to transmit the power from the engine to the front and rear axles. 

Normally, within a transfer case, there are 2 gear settings (high and low). The high gear setting is suitable for basic off-road driving conditions. For example, if you are driving in snowy, rainy, muddy, or dirt road conditions, then the high gear settings will come in handy because the high gear will offer aggressive traction.

On the flip side, low gears offer additional torque at a slower speed. This setting will come in handy in extreme off-road conditions. For example, if you are rock crawling or climbing a steep slope or hill, the low gear settings will be perfect for obtaining extra torque.

To be noted, the transfer case depends on many other parts of the vehicle for distributing the engine power to all the front and rear wheels at the same time. For example, it works in collaboration with the differentials, drive axles, wheels, transmission, driveshafts, and more. 

Also, the transfer case is impacted by any obstacles on the road, or how fast/slow you are driving, or any misalignment by the drive shaft, and so on.

Overall, you can say that the transfer case is assisting your 4WD vehicle move and stay aligned. It also helps in transmitting an equal amount of torque power to all four wheels of the vehicle. So without a transfer case, your 4×4 vehicle would not have its four-wheel-drive system.

How Transfer Cases Work

Part-time or full-time/different modes.

When it comes to a 4-wheel drive system, there are primarily 2 types of drive systems (part-time and full time). As the name suggests, a part-time drive system means that your vehicle remains in a 2-wheel-drive system most of the time. 

However, when you need the four-wheel-drive settings, you can turn the drive system from a two-wheel to a four-wheel-drive system with a push of a button or lever (depends on the particular vehicle). 

Some part-time 4WD drive systems can also switch from 2-wheel drive to a four-wheel-drive automatically, depending on the terrain condition. 

Generally speaking, most 4WD drive systems feature various modes like auto, terrain, 4-Hi, 4-Lo, etc. You can change the modes based on the driving conditions. 

On the other hand, a full-time 4WD system operates differently as you cannot usually switch between two-wheel and four-wheel-drive systems. However, you can change the gear and mode settings in the case of both part-time and full-time 4WD drive systems.

What Are the Symptoms of a Bad Transfer Case

Trouble shifting gears.

From the discussion above, you might have already guessed that the transfer case is very vital in shifting the gears of your vehicle. Shifting gears will not be a problem with a good transfer case. 

In contrast, if you have a bad transfer case, you will notice either grinding or whirring on the gears. You may also hear weird sounds coming from the vehicle while you are changing gears. In that case, the transfer case may be the culprit.

Unusual Grinding Sound

Another symptom of a faulty transfer box would be an unusual grinding sound. If you notice whirring noise coming out of the transfer case constantly, then there must be a problem with the transfer case. 

It could be that there is a lack of alignment inside the box. If you hear the unusual grinding sound occasionally, you should still consider checking the condition of the transfer box on your rig.

Erratic Four-Wheel Drive Driving

It is inevitable that if the transfer case is defective, your vehicle’s performance will worsen as well. The back wheels could fall out of alignment with time. This would put a lot of stress on the transfer case. 

As a result, the wheels could be damaged and the performance from the rear wheels will not be great. In general, you will start to notice inconsistent driving performance from your 4×4 rig . There will be problems with the transmission, gear shift, traction, and handling if the transfer case is faulty.

Smoke, Crack, and Fluid

If things go really bad, then you might even notice smoke coming from the back of your rig. If the smoke is from the transfer case, you must take care of the situation as fast as you can. 

The casing of the transfer box is made of strong metal. Still, it could get damaged if you run over a huge obstacle while overlanding . Debris could then get inside the device and damage the internal equipment, so look for cracks or crevices in the transfer case.

Remember, you need to oil the transfer case more often. There is also fluid inside the transfer case for running the gear setup smoothly. Unfortunately, if there is a crack in the T-case, the fluids could leak out. So, if you notice fluid is leaking out of the box, the transfer case could be damaged.

What Happens When A Transfer Case Goes Bad?

As we have explained above, a faulty transfer shows a few symptoms. For instance, the car will not perform the best, there will be problems with shifting gears, and you will hear unusual whirring or grinding noise from the transfer case. 

There could be smoke or fluids coming out of the transfer case as well. If any of these things happen on any of your cars, you should talk to a mechanic for repairing or replacing the transfer box as soon as you can.

Can You Drive With A Broken Transfer Case?

Yes. Technically, you can drive with a broken transfer case. However, we don’t recommend it, so make sure you have fixed the issue as quickly as possible.

How Can You Prevent Damage To Your Transfer Case?

Here are a few tips that will come in handy if you want to take care of the transfer box in your vehicle.

• You should shift gears as gently as possible
• Use the 2-wheel drive system whenever possible. If the terrain condition is perfect, the 2-wheel-drive system is enough
• Follow the owner’s manual
• You must check and maintain the transfer box more often if you are an off-roader
• If possible, try to minimize off-roading with the 4WD drive system engaged
• Do not put more stress on the transfer box by overusing it
• If possible contact an expert mechanic in the field to check the transfer case now and then

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Transfer Case Fluid Change

REQUIRED FLUID

1983-1990 – Use Dexron II automatic transmission fluid when refilling or adding fluid to the transfer case.

1991-2007 – Use Mercon automatic transmission fluid when refilling or adding fluid to the transfer case.

2008-2011 – Use Motorcraft Transfer Case Fluid XL-12

LEVEL CHECK

1.   Position the vehicle on level ground.

2.   Remove the transfer case fill plug (the upper plug) located on the rear of the transfer case.  The fluid level should be up to the fill hole.

3.   If lubricant doesn’t run out when the plug is removed, add lubricant until it does run out.

4.   Replace the fill plug.

The transfer case fill level check plug is the upper most plug located at the rear of the case (See red arrows in photos above and below).  Remove the plug using a 3/8 in. drive ratchet.

DRAIN & REFILL

The manufacturer recommends that the transfer case fluid should b changed every 60,000 miles (96,000km).  However, if the truck is drive deep water (as high as the transfer case housing) it is a good idea to replace the fluid.  Little harm can come from a fluid change when you just purchased a used vehicle, especially since the condition of the transfer case fluid is usually not known.

If the fluid is to be drained, it is a good idea to warm the fluid first so it will low better.  This can be accomplished by 15-20 miles of highway diving.  Fluid which is warmed to normal operating temperature will flow faster, drain more completely and remove more contaminants from the housing.

1)   Drive the vehicle to assure the fluid is at normal operating temperature.

2)  Raise and support the vehicle securely on jackstands.  Remember that the vehicle must be supported level (usually at four points) so the proper amount of fluid can be added.

3)  Place a drain pan under the transfer case housing, below the drain plug.  Remember that the fluid will likely flow with some force at first (arcing outward from the transmission), and will not just drip straight downward into the pan.  Position the drain pan accordingly and move it more directly beneath the drain plug as the flow slows to a trickle.

*To insure that the fill plug is not frozen or rusted in place, remove it from the transfer case BEFORE removing the drain plug.  It would unfortunate to drain all of your transfer case fluid and then realize that the fill plug is stripped or frozen in place.

4. )   Remove the fill plug, then the drain plug and allow the transfer case id to drain out.

The transfer case drain plug is usually a square receiver which is signed to accept a 3/8 in. driver such as a ratchet or extension.

5)  Once the transfer case has drained sufficiently, install the drain plug until secure.

6)  Fill the transfer case to the proper level with the required fluid.

7)  Reinstall the filler plug once you are finished.

8)  Remove the jackstands and carefully lower the vehicle.

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MOTORCRAFT ®

TRANSMISSION FLUID

Transfer case fluid.

• Motorcraft Synthetic Blend MERCON ® V Automatic Transmission and Power Steering Fluid is a high-quality automatic transmission fluid recommended by Ford Motor Company. It was developed for use in the newer electronically controlled automatic transmissions built after 1989 and power steering systems built after 1998 requiring MERCON ® V or MERCON ® fluid
• Motorcraft Synthetic Blend MERCON ® V Automatic Transmission and Power Steering Fluid is formulated with high-viscosity index, premium-quality, synthetic/hydroprocessed base oils and specially designed performance additives. It is specifically formulated to provide improved shifting characteristics at high and low ambient temperatures, excellent thermal and oxidation resistance, and good low temperature fluidity. It provides wear protection and inhibits the formation of gum, sludge, lacquer, and foam. It also provides protection against rust and corrosion
• It is especially effective in applications where high temperatures are a concern. Due to its excellent thermal, oxidative, and shear stability, this fluid is required in manual transmission applications such as Mustang with G1 manual transmissions and F/E series with TR 3650 and ZF S5-47 manual transmissions
• Formulated for power-steering systems to provide excellent low temperature fluidity as well as improved high temperature thermal stability for use in extreme conditions in all seasons
• Do not use in applications where MERCON ® LV, MERCON ® SP, Continuously Variable Chain Type Transmission Fluid, Motorcraft ® Premium Automatic Transmission Fluid, FNR5 Automatic Transmission Fluid or Type F Automatic Transmission Fluid is recommended

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Fluid Suggestions by Transfer Case Type

DISCLAIMER: The information shown below was obtained from reliable sources and is believed to be accurate and complete at the time of publication. Although this information is believed to be accurate and complete, no liability can be assumed for any incomplete or incorrect data. Always verify with the manufacturer of your vehicle for the proper fluid to use in your transfer case.

When you consider that your transfer case is always working (even when you’re in two-wheel drive) it should come as no surprise that proper fluid use and maintenance is important for the life of the transfer case. The fluid in the transfer case serves as both lubricant and helps to keep the internal components cool and turning smoothly. Replacing this fluid at appropriate intervals can help prevent premature wear and damage caused by contaminated or broken-down fluid.

Additionally, if the transfer case fluid level is low, the entire transfer case should be inspected for leaks and damage. Many mechanics (and some manufacturers) recommend that you replace the transfer case fluid at least every 30,000 miles. When the fluid is replaced, pay careful attention to the fluid you are draining; if there is a burnt smell or dark brown color or metal flakes or sheen, your transfer case may be damaged.

Transfer case fluid is responsible for keeping the components of the transfer case well lubricated. When this fluid leaks out or becomes contaminated, it is no longer able to act as a lubricant, and severe damage can be caused to the transfer case.

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2014 CTS 3.6 AWD transfer case fluid change

• Add to quote

I am guilty of consuming information on vehicle forums for many years with few posts myself so wanted to take an opportunity to contribute some good news here. After reading several posts about the potential difficulty in changing the transfer case fluid on my 2014 CTS (3.6L / AWD) I was leaning toward taking it into the shop for this service. Some owners even needed to custom fabricate their own tools to access the fill hole bolt - definitely above my ability. Luckily I decided to get underneath the car to confirm this before calling the shop and was pleasantly surprised to find completely clear access to both the fill and drain locations - see photo. The fill bolt needed an 8mm hex drive and the drain bolt came off with just the square head of a 3/8" ratchet. I attached a fill tube to a quart of transfer case fluid and squeezed nearly all of it in. Total time about 15 minutes for the job. Hope this helps some reluctant owners to check the setup under their car and proceed with the service themselves.  

Attachments

Didi you do the rear differential too? If so, was that just as easy?  

No - manual listed fluid change only with limited-slip version on CTS-V.  

I'd do the rear at least once regardless of what the manual says. I did mine and the worst part was trying to use a funnel and tilt the bottle. Not enough room to tilt. After frustration and a mess I switched to a fluid pump.  

Is it a fairly straight forward procedure?  

Yes. Drain out the bottom and fill from the side till it runs out. Hardest part was making sure I picked the correct fluid. They often discontinue part numbers and you have to find the current substitute. I start with the owner manual GM number, then check multiple websites until I find a consensus. I used AC Delco fluid. Buy a little more than the book capacity, you can't trust that 100% and you may spill. Last thing you want is to be stuck half done.  

Thanks!  

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