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  1. #1

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

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


  2. #2
    Master Mechanic Silverado Junkie's Avatar
    Join Date
    Feb 2010
    Lead Hill, Arkansas


    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.
    1995 Silverado,Z71, 3-inch lift,2-inch leveling kit, SkyJacker Suspension, short ram-air intake, throttle body spacer, MSD ignition coil, straight pipes

  3. #3


    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.
    When you hear hoofbeats, look for horses not zebras.

  4. #4


    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

    2009 Chevrolet Silverado 1500 LT Z71 Crew Cab "All-Star Edition"

    Line-X'd Bed
    Line-X'd Custom Brush Guard(Heavy Duty)
    5.3L Flex Fuel
    275/65R18 Toyo Open Country AT2's
    2" Rough Country Leveling Kit(want to get the 2.5 RC kit)
    EGR In-Channel Vent Visors
    Exterior PLUS Package
    Interior PLUS Package
    K&N Drop-In Air Filter
    Cat-Back Dual Exhaust
    Black Bowties
    Diablo Sport Predator(AFM Disabled)
    Towing Mirrors
    Next Planned Mods
    Blacked out Tail Lights
    Aftermarket Rims

  5. #5


    Quote Originally Posted by ChevyBoy2003 View Post
    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
    Can't go wrong with Mobil 1. Autozone stocks it in both the 90 and 140

  6. #6


    so what weight for each??

  7. #7

    Cool how do i change the fluid in my transfer case and diff?

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

  8. #8


    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. #9


    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

    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 by ChevyBoy2009; 06-09-2010 at 04:43 PM.

  10. #10


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

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