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Rear Diff Fluid 2003 Silverado 4x4

Discussion in 'Maintenance & Upkeep' started by ChevyBoy2009, Sep 26, 2010.

  1. ChevyBoy2009

    ChevyBoy2009 Rockstar 4 Years 500 Posts

    Hello i have a 2003 Chevy Silverado 1500 LS 4x4 (on floor) with the 4.8L. I bought the truck at 100k (truck has 115k now) and i never asked the guy if he ever did the rear end fluid so now im gonna do it just to be safe.The ?'s i have are what weight i should use,i was thinking Mobil 1 75-90 fully synthetic.I hardly pull anything,maybe a small pop-up camper and maybe alittle trailer with a zero-turn mower on it.And the next ? i have is where is the drain plug?...i saw a plug in the back and close to the top of it but how does it drain then?...and how many quarts does it hold?
    Last edited: Sep 26, 2010
  2. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    The Mobil 1 is great gear lube. You have to remove the rear pan to drain/change the fluid. After draing I always clean the housing/gears with brake clean and spin the rear so I can look at all the ring&pinion teeth. Holds 2-3 qts.
  3. ChevyBoy2009

    ChevyBoy2009 Rockstar 4 Years 500 Posts

    k should i replace the gasket and cover or just the gasket??...and is 75-90 the right stuff??...amd i assume the back plug i found is the fill plug,and should i fill it till it drips out or alittle bit down??
  4. ntbush83

    ntbush83 Rockstar 4 Years ROTM Winner 1000 Posts

    So after you do that you just put the pan back on and fill her up to the top?
  5. ChevyBoy2009

    ChevyBoy2009 Rockstar 4 Years 500 Posts

    i believe so
  6. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    Yes buy and install a new gasket. The plug near the top and towards the front of the differential is the fill plug. Fill slowly till fluid comes out. You use a socket extension to remove the plug.
  7. ChevyBoy2009

    ChevyBoy2009 Rockstar 4 Years 500 Posts

    k i will buy a new gasket,3 bottles of Mobil 1 75-90 FS and clean everything and then fill it till it comes out....and that should last me what 75k or ??...and any additives or no?? Thanks Nick
    Last edited: Sep 26, 2010
  8. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    That should do it.
  9. ChevyBoy2009

    ChevyBoy2009 Rockstar 4 Years 500 Posts

    i just called Advanced Auto Parts and they said i just need to use RTV and make my own basically,but does that sounds right?...or should i try somewhere else??...and they have Mobil 1 for 10.68 a bottle??
  10. ntbush83

    ntbush83 Rockstar 4 Years ROTM Winner 1000 Posts

    Also do I need a certain type of fluid since mines a 2500 and I pull a lot?

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