Maintenance Tips: What Fluid Goes In A Duramax Transfer Case

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If you own a 4WD or AWD, a transfer case is crucial to your truck. The transfer case divides the torque from the transmission to the front and rear axles. Proper maintenance that includes the right fluid allows you to focus on driving and forget the problems. That is why you should know what fluid goes into a Duramax transfer case.

So, what fluid goes in a Duramax transfer case? Truck owners usually already have their favorites. The best results in maintaining the optimal working conditions show the Dexron Vi Automatic Transmission Fluid. Also, Merchant automotive transfer case fluid has great features. Auto Trak II, transfer case fluid, is another oil well-regarded in the truck world.

duramax transfer case fluid change

Using the wrong fluid can shorten work life and lower performance. That is why you should always choose the proper fluid. Replacing a transfer case fluid is easy, and we will also cover it. We also gathered some of the most interesting questions about this topic and answered them for you. Enjoy! 

What Is The Importance of Using the Right Fluid for Your Duramax Transfer Case

A transfer case has several gears, depending on the vehicle and the engine type. Those gears require lubrication to work properly. Over time the oil may get contaminated with metal shards that can damage the transfer case. So, lubrication and contamination are the main reasons for changing the transfer case fluid.

Recommended periods for replacing the fluid are in 20-30,000 mile intervals. That depends on the type of fluid and the vehicle. Using higher-quality fluid will result in better transfer case performance and longer life.

Extends the Life of Your Transfer Case

Like all other components that require lubrication, the transfer case will also have a longer work life if using quality oil. The average work life of a transfer case is between 150,000 and 200,000 miles. The transfer case life will extend closer to 200,000 miles with better oil. 

Improves the Performance of Your Duramax 

The purpose of the transfer case is to ease the power transfer to each axle. It also divides the power equally and synchronizes the work of all wheels. It works in cooperation with the transmission. Using an excellent product with proven quality will make its daily work easier. The gears will shift smoothly, and you won’t notice a thing.

How To Choose the Correct Fluid for Your Duramax Transfer Case

Manufacturer’s Recommendation

Every manufacturer has its recommendations for all the fluids that are used. Chevy recommends brands like Auto Trak and Mobil. These are high-quality products that will work great with its transfer case.

Learn Viscosity Ratings and Specifications

Transfer case uses high-viscosity fluids, and the typical value is 70W-90. Each part must be properly lubricated, and that is why the viscosity is so high. This fluid needs to be thick to protect the components from frequent shock. 

The viscosity rating of a transfer case fluid is completely different from the one used for the transmission. 

How To Change the Fluid in a Duramax Transfer Case

Replacing the transfer case fluid is simple and very similar to changing the manual transmission fluid. For this procedure, you will need the following:

  • Drain pan
  • Socket
  • Wrench
  • A funnel.

Prepare Your Vehicle for Fluid Change

  • Position the truck on a flat surface and turn off the car
  • Place jack stands to lift up the vehicle
  • Check if everything is safe before proceeding

Drain and Replace the Transfer Case Fluid

  • Place the drain pan under the transfer case
  • Remove the drain plug
  • Check the drain plug for metallic buildup
  • Clean the plug and reinstall it
  • Refill the fluid with the help of a funnel.

If you find a larger buildup on the drain plug, the components’ wear and tear is evident. You should inspect the transfer case altogether. Also, always add the recommended amount to the case when adding fluid. In the case of a Duramax, it is 2 quarts of fluid. 

Fluid Change Safety Measures

We recommend using safety goggles for oil splashes. It is worth knowing that the fluid will come pouring out as soon as you start unscrewing the plug. Be ready for it.

Common Mistakes to Avoid When Choosing Duramax Transfer Case Fluid

It is essential to choose the right fluid. You need to check the viscosity ratings and the manufacturer’s recommendation. The next important thing is to change the fluid regularly.

Inappropriate Viscosity Ratings

Choosing the wrong viscosity fluid will cause excessive wear to the components in the transfer case. The fluid must have high viscosity ratings to keep the case well-lubricated. If the fluid flows too much through the system, it cannot adequately protect the parts from damage.

Neglecting Manufacturer’s Recommendations

It is important to check the owner’s manual and recommendations regarding the replacement interval of the fluid. During work, metal shavings will break off the components and end up in the fluid. If the fluid is too dirty it will cause problems for the whole transfer case. Also, the fluid loses its features as time passes, so it must be replaced regularly.

Tips To Maintain Your Duramax Transfer Case

The best way to maintain the transfer case is to follow the user’s manual recommendations. That includes the period when you replace the fluid and the type of fluid you will use. That way, you won’t get into a situation where you need to repair or replace a part because of improper maintenance. 

Even if you disregard the recommendations from the manufacturer, try to listen to the car. If you notice anything strange happening that can be connected to the transfer case, consult a mechanic. 

Fluid Inspection and Replacement regularly

You can easily inspect transfer case fluid and need the flashlight. Remove the top fluid fill plug and check it under the flashlight. The level of fluid should be just below the top hole. 

You should note when you replaced the fluid the last time, so you don’t need to think about it. It is recommended to change the fluid every 20,000 to 30,000 miles.

Check Out This Is What Happens If You Never Change Your Transfer Case Fluid:

Detecting Early Signs of Transfer Case Issues

The most common signs of problems with the transfer case are:

  • Grinding noises coming from under the vehicle
  • Problems when shifting gears
  • 4WD or AWD warning light turns on
  • Fluid leaks under the vehicle.

When you notice any of these symptoms, visit a mechanic. If you delay resolving the issue, it will become more complicated and expensive.

See Also: Car Gears Meaning: What Does The S Stand For On The Gear Shift? (Automatic Transmission Sports Mode)

FAQs

What is the capacity of a Duramax transfer case?

The capacity of a Duramax transfer case is 2 quarts of fluid. Do not add more fluid because it will cause problems for the transfer case.

Can ATF fluid be used in a transfer case?

Yes, it can. The transfer case can be filled with gear oil, automatic transmission oil, or specialty lubricants.

Can I put ATF 4 in my transfer case?

ATF 4 fluid is recommended for Chevy and Chrysler vehicles, so you can use it.

How much oil do I need for a transfer case?

The transfer case in a Duramax can take up to 2 quarts of transfer case fluid. Adding more is dangerous, so avoid it.

Final Considerations

If you use your truck for off-road driving or tow heavy loads, you need to know something about the transfer case. Without it, the power cannot be passed properly to the axles. The transfer case uses special lubrication fluid to work. The components of the case need to be heavily lubricated. That is why the fluid has a high-viscosity rating.

The Duramax engines require 2 quarts of transfer case fluid. You can choose from several product brands, like Dexron, Auto Trak, and Mobile. It is very important to keep the transfer case well-maintained. So keep an eye on the time interval for the fluid change, and always listen to your truck. 

For more advice about Duramax maintenance, stay with us!

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Pedro is a skilled automotive expert whose roots trace back to his apprenticeship with the AYES program at PCTI Automotive Technology. There, he distinguished himself by securing state-level accolades in the Ford competition designed for AYES-certified mechanics. In addition to his hands-on technical prowess, Pedro boasts extensive experience in sales, notably within the electrical supply sector.