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2500 HD Diff Fluids

Discussion in 'Chevy Trucks' started by JCI Trans, Apr 1, 2009.

  1. JCI Trans

    JCI Trans Senior Member
    Messages: 315

    I was looking for opinions on front diff fluids on a 2002 2500hd. I currently Run Amsoil Heavy Duty synthetic on the rear (75w90 if i remember correctly) Should i run the same in the front or should i go a little bit lighter since it only sees occassional use??? Thanks for any input!

    NICHOLS LANDSCA PlowSite Veteran
    Messages: 4,362

    Use the same. Besides what lighter oil would you use? 75-90 is the lightest gear lube available.
  3. JCI Trans

    JCI Trans Senior Member
    Messages: 315

    Ok sounds good, i'm gonna double check the weight of the fluid in the rear and probably use the same up front. thanks for the response
  4. RAZOR

    RAZOR Senior Member
    Messages: 343

    I have an 03 and the owners manual calls for 80W-90 in the front diff. That is what I have been using but I hear synthetic 75W-90 would be just as good or even a better choice.
  5. Cosmic Charlie

    Cosmic Charlie Senior Member
    Messages: 237

    2004 HD 2500 - Chevy dealer told me the rear fluid is synthetic and has no gasket (uses RTV silicone), but the front is NOT synthetic and has a paper gasket. He said to run not synthetic in my front dif .... and replace the paper gasket as well ... something about leaks at the gasket ...

    That sound right ?
  6. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    There are no paper gaskets in the front diff on these trucks...they're assembled with RTV.

    What your dealer was likely referring to was an old TBS from AMM (the diff manufacture) about not using synthetic fluid in the diff due to it's claimed incompatibility with the RTV that some pre-mid '04 model years diffs were assembled with....but I've yet to see a problem that was directly related to the synthetic oil and its incompatibility with "certain" used RTV...I run synthetic in the all the time regardless of year.
  7. JCI Trans

    JCI Trans Senior Member
    Messages: 315

    Sythetic it is! :drinkup:
  8. aeronutt

    aeronutt Senior Member
    Messages: 262

    We really need a smiley with a dead horse being beaten. Amsoil is my number one choice too.
  9. JCI Trans

    JCI Trans Senior Member
    Messages: 315

    ha that would be great
  10. RichG53

    RichG53 PlowSite.com Addict
    Messages: 1,135

    B&B is a synthetic blend ok to use.??? Or should it be pure synthetic???

    Thanks Rich...
  11. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    If your going to make the switch then go all the way. Why run a half synthetic fluid at an extra cost? Never made sense to me...or to any fluid experts I've ever spoken to. :D
  12. RichG53

    RichG53 PlowSite.com Addict
    Messages: 1,135

    OK ! ! Thanks........
  13. raceman6135

    raceman6135 Member
    Messages: 61

  14. cmo18

    cmo18 Senior Member
    Messages: 815

    A dealer once told me that they made synthetic blend to convert to full synthetic over a period of time. What do you guys think? Is it bad for the seals to just switch to synthetic?
  15. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Thats borderline amusing right there.

    You were lied to...or grossly misinformed with that false statment. ;)