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How do I change the fluid in my transfer case and diff?

Discussion in 'General Chevy & GM Tech Questions' started by blackrat, May 27, 2010.

  1. blackrat

    blackrat New Member

    Can I do this myself?
    How?
    What weight replacement fluid?
    How much?
    Should I go synthetic?
    What brand?


    Thanks
    Wade
     
  2. Silverado Junkie

    Silverado Junkie Rockstar 4 Years 500 Posts

    Front diff you remove the drain plug then when its drained out put the plug back in, then take out the fill plug at the top of your differential and fill it up until you can touch fluid with the end of your finger. For the rear, depending on the vehicle, because some have drain plugs in the transfer case and some dont. For the ones with drain plugs for the rear end, do it like your front diff. For ones without plugs, remove the rear differential cover. Be sure to loosen the bottom and let the fluid drain then take off the cover and put a new gasket on and put cover back on. Then fill fluid with drain plug at the top of transfercase until you can feel it with your finger. For fluid weights, use 80w-90 weight for regular fluid and if you use synthetic use 75w-140.
     
  3. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    Need to know what vehicle you have to give specific advise. But generally speaking - make sure you can get the fill plug out BEFORE draining any fluid. Axle lube, I agree with above poster. 75W-140 synthetic is the first choice, 80W-90 Dino is the second choice. And I fill the till they are overflowing.

    We need to know what vehicle & transfer case you have to prescribe lubricant for it. NP205 gets 75W-90 Synthetic or Dino. AutoTrac cases get GM's own AutoTrak II fluid ONLY. The rest of the chain driven cases get ATF, I highly highly highly recommend synthetic ATF, or synthetic Manual Transmission Lube if you can get it.
     
  4. ChevyBoy2009

    ChevyBoy2009 Rockstar 4 Years 500 Posts

    I have and 03 Silverado 1500 LS 4x4 with the 4.8l and i was wondering what front diff fliud i would need and what rear end fluid i would need....i was thinking Mobil 1 fully synthetic
     
  5. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    Can't go wrong with Mobil 1. Autozone stocks it in both the 90 and 140
     
  6. ChevyBoy2009

    ChevyBoy2009 Rockstar 4 Years 500 Posts

    so what weight for each??
     
  7. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    ChevyBoy2003, I used the Mobil 1 75/90 in the front and rear.
     
  8. timmyfixit

    timmyfixit New Member

    Royal Purple Synchromax can also be used in the Autotrac transfer cases, at least according to Royal Purple..

    Just changed the differential and transfer case fluids on mine a couple weeks ago.
     
  9. ChevyBoy2009

    ChevyBoy2009 Rockstar 4 Years 500 Posts

    k my truck has 112k on it and runs great just doing a few things to it since i got it at 100,300 miles!

    What ive done...

    Undercoated rocker panels
    Mobil 1 FS in motor
    285/75R16 Nitto Terra Grapplers
    New Serpentine belt and AC belt
    Debadged


    So u think doing this is a good idea?...idk when it was last changed or if it has been....and do i have a drain bolt
     
    Last edited: Jun 9, 2010
  10. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    140 is good in the rear, especially if you carry heavy loads or do any towing.
     

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