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front & rear diff. & transfer case fluids

Discussion in 'General Chevy & GM Tech Questions' started by redneckarmyMP, Aug 13, 2009.

  1. redneckarmyMP

    redneckarmyMP Epic Member 5+ Years 500 Posts

    i figure its about time i check and/or replace the fluids in my front and rear differentials as well as the transfer case.but....i have no idea what im looking for or where to begin.anybody had experience on this?what fluids do i need?where can i get em?and how much of a task am i lookin at here?
  2. Jimmiee

    Jimmiee Epic Member 5+ Years 1000 Posts

    The good news is all 3 units take 75-90 Synthetic Gear Lube. The front diff and transfer case have a drain plug which is easy. The rear diff requires R&R of the cover. Just buy a tube of High Temp Black Silicone Sealer for the rear diff. Make sure to scrape all the old gasket off the cover and diff housing. Put a rag over the gears so you won't get crap inside while scraping. Clean both surfaces with brake cleaner and run a big bead of sealer around the cover. Install the cover and let it dry for about an hour. You don't have to wait a whole hour but it won't hurt to let it set up before adding oil.
  3. Jimmiee

    Jimmiee Epic Member 5+ Years 1000 Posts

    I forgot to mention you will need a shade over 5 quarts of lube so buy 6 to be safe.
  4. cindon27

    cindon27 New Member

    The front and rear differentals I put in MOBIL1 synthetic gear oil. You can buy it at any car parts store like NAPA. There are 2 plugs in the diff. 1 on the bottom(drain) and 1 up above the halfway point in the diff (fill hole). It drains faster if you take them both out. As for the transfer case Its very similar as it also has 2 plugs which you use the same way.If you decide to go with synthetic in the diff's then you might want to put synthetic in the transfer case as well.
  5. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    Hey Jimmlee, doesnt it depend on the transfercase you have. I have a 246 and was told to use the auto-trak ll fluid. I do use Mobil 1 in the diffs. Can you use Mobil 1 in the 246 case??? Thanks.
  6. cindon27

    cindon27 New Member

    Are you sure that your rear diff. doesn't have a drain plug? Even the rear diff. usually has a drain plug.
  7. cindon27

    cindon27 New Member

    My transfer case requires DEXRON VI in the 2006 silverado.
  8. redneckarmyMP

    redneckarmyMP Epic Member 5+ Years 500 Posts

    thanks jimmiee very helpful.ill try to get that done this weekend and let you know how it went
  9. Z71_guy

    Z71_guy Epic Member 5+ Years 1000 Posts

    if you have push button 4wd switch it takes auto track 2
  10. Jimmiee

    Jimmiee Epic Member 5+ Years 1000 Posts

    Good point. There's more than one transfer case option

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