Changing your transfer case fluid
Posted on Jan 28, 2009 by Josh Merva in How To
This article was originally submitted in 2004 by Tom Fraley aka MountaineerTom. Thanks Tom!
Changing the transfer case fluid is a pretty straightforward job. If you have the manual transfer case (lever actuated), use DEXRON-III Automatic Transmission Fluid. If you have an automatic transfer case (push button actuated), you should use the fluid that GM recommends. Some owners’ manuals may say to use Automatic Transfer Case Fluid (GM Part No. 12378396), which is a reddish colored fluid. GM has a new Auto Trak II Transfer Case Fluid (GM Part No. 12378508), which has a bluish color to it. The newer fluid has better friction modifiers. While your doing the job, it’s a good idea to change the drain and fill plugs (GM Part No. 15032997) out too.
Auto Trak II Transfer Case Fluid (Part No. 12378508) and Replacement Drain Plugs (Part No. 15032997)
First thing you should do is remove the transfer case skid plate for easier access. Only four bolts to remove. (15mm)
Remove Skid Plate Bolts
After removing the skid plate, the drain and fill plugs (18mm) will be very easy to get to. Remove the plugs and let the old fluid drain out. Be ready for the fluid to shoot out pretty far, so keep that in mind when positioning your drain pan.
Plug Locations
All that is needed to do now is reinstall the drain plug, torque to 15 ft. lbs., and refill the transfer case with fluid until the fluid level is even with the bottom of the fill hole. Basically, fill it up until the fluid runs out the fill hole. It takes almost 2 quarts to fill it up. To make the fill up easier, you may want to purchase a pump at a local auto parts store. These are very handy, don’t cost a lot, and will fit on gear oil bottles for when you go to change your differential fluids.
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milo thornton
05. Oct, 2009
you are wrong (but not the only one!) on the description of auto v manual transfer cases.
all gm transfer cases (my research in the context of silverado 2500hd) which have push button select are manual transfer cases.
Mitch Rapp
13. Feb, 2010
Just did this and the instructions were excellent. Thanks. It took just about 2 full qts before the fluid began running out of the fill hole. At $11.49/qt at the dealer for Auto-Trak II fluid, I didn’t want to spill a drop.
According to my dealer, you can identify the the Automatic Transfer case by the 4 push button switches on the dash. The big round “Auto 4WD” switch is the key and indicates that you need Auto-Trak II fluid. Of course the other switches are 2HI, 4HI and 4LO. If you don’t have the Auto 4WD button, it is considered a manual transfer case.
My truck is a 2001 GMC Sierrra that I just bought with 142,000 miles on it. Decided to change all the fluids since I didn’t know when they were previously changed. I was shocked to find less than a pint of fluid in the transfer case when I drained it!!!!
Dave Hare
19. Jun, 2010
I own a 2007 Silverado 2500HD. I looked in the owners manual and it says the transfer case uses GM DEXTRON IV fluid which is the latest automatic transmission fluid. This Silverado has the electronic dial type 4×4 switch on the dash near the AC controls. Q, Why do I need to replace the drain and fill bolts?
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Doug
27. Aug, 2010
These intructions were perfect, did the drain and refill in less than 30 minutes. Thanks