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What fluid to use in GM transfer case?

For most GM transfer cases, Dexron VI automatic transmission fluid (ATF) is the recommended option. Always verify the exact specification in your owner’s manual or on the transfer case label, since some older GM units may require Dexron II/III or a different fluid specification.

The transfer case is a critical component of GM’s four‑wheel‑drive system, passing power to the driveshafts and engaging low-range gears as needed. Fluid choice affects lubrication, engagement smoothness, and overall durability. With a wide range of models and years, the official specification can vary, so confirming the exact requirement for your vehicle is essential before you fill or refill.

Understanding fluid requirements for GM transfer cases

GM has used a few different fluid specifications across generations. Dexron VI ATF has become the standard for most modern GM transfer cases, offering backward compatibility with older Dexron II/III specifications. However, some older vehicles or specialized transfer-case designs may call for Dexron II/III or, in rare cases, a dedicated gear oil. Always cross-check with the owner’s manual, the transfer-case tag, or a GM dealer to avoid mismatches.

Common guidance you may encounter when reviewing manuals or service literature:

Dexron VI automatic transmission fluid (ATF) is the most widely recommended fluid for contemporary GM transfer cases.

Dexron II/III ATF may be specified for older GM transfer cases; Dexron VI is typically backward-compatible but the manual will confirm the exact spec.

Some very old or specialty GM transfer cases might require a dedicated gear oil (GL-4) rather than ATF; if this is the case, the manual will specify it.

In practice, starting with Dexron VI ATF is a sensible default for many GM vehicles, but never assume—the exact requirement depends on the model year and transfer-case design.

Steps to check or replace GM transfer case fluid

Following a careful procedure helps ensure the correct fill level and fluid type while minimizing contamination.

Park on a level surface and engage the parking brake; allow the transfer case to cool if it has been in operation.

Locate the transfer-case fill plug on the side or rear of the case and remove the plug to inspect the fill level.

Check the fluid level; it should be at the edge of the fill hole. If low, add Dexron VI ATF gradually until it begins to seep from the fill hole.

Use the appropriate tool and container to pour in the correct fluid, avoiding mixing in incompatible fluids.

Reinstall the fill plug securely and, after a short drive, recheck for leaks and proper 4WD engagement.

Regular checks help maintain proper lubrication, extend the life of the transfer case, and ensure reliable engagement of 4WD modes, especially under heavy towing or off-road use.

How to confirm the right fluid for your GM vehicle

The most reliable source is your vehicle’s manual. If the manual is missing, contact a GM dealer or use the vehicle identification number (VIN) to pull the exact specification from GM’s service resources. The transfer-case code, often stamped on the case, can also indicate the correct fluid type and capacity for your model and year.

Summary

Dexron VI ATF covers the majority of GM transfer cases in contemporary vehicles, but always verify with official documentation for your exact model and year. Using the wrong fluid can lead to poor shifting, accelerated wear, or leaks. When in doubt, consult the owner’s manual, check the transfer-case tag, or ask a GM-certified technician to confirm the correct specification and capacity for your vehicle.

What kind of fluid do you put in a transfer case?

The correct fluid for a transfer case depends on the vehicle, but it's most often either automatic transmission fluid (ATF) or a specialized transfer case fluid. Some older vehicles may use a heavier gear oil, so it is essential to consult your owner's manual to determine the correct type and specification for your specific make and model.
This video demonstrates the process of changing the transfer case fluid: 1mChrisFixYouTube · Oct 14, 2013
Common transfer case fluids

Automatic Transmission Fluid (ATF): Many modern vehicles use ATF in the transfer case, especially those with hydraulic systems. The specific type, such as Dexron VI, is crucial and should be matched to the manufacturer's recommendation.
Specialized Transfer Case Fluid: Some vehicles require a specific fluid designed specifically for the transfer case. These fluids are formulated to protect against wear, corrosion, and foaming, and may be synthetic or conventional.
Gear Oil: Older 4x4 vehicles often use a heavier gear oil, such as an 80W-90, which is also used in differentials and manual transmissions.

How to find the right fluid

Check your owner's manual: This is the most reliable source for determining the correct type of fluid and any specific requirements, such as viscosity and API specifications.
Look for a label: Some transfer cases may have a sticker or label indicating the fluid type.
Consult a professional: If you are unable to find the information, a mechanic or parts store can help you identify the correct fluid for your vehicle.

What kind of fluid does a 2015 GMC Sierra transfer case take?

Default Qty 2 - 1-liter bottles of synthetic RAVENOL Dexron® VI ATF. High-performance replacement or equivalent to the original recommended DEXRON-VI Sierra transfer case fluid.

What kind of fluid does a Chevy 2500hd transfer case take?

The correct transfer case fluid for a 2500HD is typically Dexron VI automatic transmission fluid (ATF). Some older models (pre-2006) may use Dexron III, and those with an automatic four-wheel drive system might require Auto-Trac II, so it's best to confirm the specific model year and option by checking the owner's manual or the label on the transfer case fill plug.

By model year

2006 and older: May use Dexron III or equivalent. If it's an automatic four-wheel drive system, it may require Auto-Trac II.
2007 and newer: Use Dexron VI ATF.

Before you begin

Always check the fill plug: This is the most reliable way to confirm the correct fluid type for your specific vehicle.
Identify your system: Some automatic transfer cases may require a specialized fluid like Auto-Trac II.
Consult your owner's manual: It will have the definitive answer for your truck's make and model year.

How much fluid does a GM transfer case hold?

The fluid capacity for a GM transfer case varies by model, but many common GM trucks and SUVs require between 1.5 to 1.6 quarts of DEXRON-VI automatic transmission fluid. For some models, the capacity is around 2.5 quarts, while some heavy-duty models may require closer to 3 quarts. Always consult your owner's manual or check your RPO code for the precise capacity and fluid type for your specific vehicle.

Vehicle Type	Fluid Capacity	Fluid Type
Many 1500 Silverado/Sierra models	1.6 quarts	DEXRON-VI ATF
Some Full-Size Trucks	2.5 quarts	DEXRON-VI ATF or Full Synthetic 5W30
Heavy-Duty Models	3 quarts	DEXRON-VI ATF

Some older models may use different fluids, such as Autotrac II fluid.
It's a good idea to buy a little extra fluid, as you may not be able to drain all of the old fluid out.
Always follow the manufacturer's recommended procedure for checking the fluid level.

Kevin Bennett

Company Owner

Kevin Bennet is the founder and owner of Kevin's Autos, a leading automotive service provider in Australia. With a deep commitment to customer satisfaction and years of industry expertise, Kevin uses his blog to answer the most common questions posed by his customers. From maintenance tips to troubleshooting advice, Kevin's articles are designed to empower drivers with the knowledge they need to keep their vehicles running smoothly and safely.