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91 GMC rear seal leak

Discussion in 'Chevy Trucks' started by bison1973, Dec 12, 2003.

  1. bison1973

    bison1973 Member
    Messages: 69

    I'm pretty sure the rear seal on my 1991 GMC 1/2 4x4 is leaking-lots of oil coming from that area. How is the seal replaced? Is it fairly easy-like through the oil pan? What has to be done? Thanks in advance.

  2. sonjaab

    sonjaab PlowSite.com Addict
    Messages: 1,425

    TIM...These new GMs have a 1 piece "O" seal.

    You have to drop the tranny and pull the seal out
    from the rear of the motor.
    No more 2 piece deals anymore...........geo
  3. CHPL

    CHPL Member
    Messages: 82

    make sure it isnt leaking from the oil filter adapter before you pull the tranny out
    i have seen the O-ring on the adapter get brittle and split and the oil runs down the flywheel cover.