1987 K20 Auto Transmission

Discussion in '1973-1987' started by gpkatz, Feb 24, 2008.

  1. gpkatz

    gpkatz Member

    Joined:
    Feb 24, 2008
    Messages:
    2
    My 87 truck goes into all forward gears but does nothing in reverse. Can anyone help. One person said that I have a 700r4 Transmission and that the reason that forward works and not reverse is because they are separate packs. Does this mean I can replace just the reverse or rebuild just reverse? I would also need a source for a new one if that is the answer.
     
  2. liftedK10

    liftedK10 Member

    Joined:
    Jan 17, 2008
    Messages:
    11
    Location:
    upstate ny
    does your trans slip at all while in drive, if the problem is strictly reverse then it is probably the sungear, the teeth on the gear get stripped. if it has a lot of miles on it and you dont want to rebuild it i would suggest finding a good junkyard trans or a reman unit with a warranty. if you are goin to take the time to fix the trans yourself you will want to replace all the clutches and steels and bushings anyway, and go through the valve body. it only makes sense to freshen the whole trans up while you have it out. but the rebuild kit and any hard parts you will need may put you over the cost of a good used or reman trans anyway, you wont know until you tear it apart.
     
  3. gpkatz

    gpkatz Member

    Joined:
    Feb 24, 2008
    Messages:
    2
    Thank you

    No, It is not slipping. The transmission has about 80k on it. I have been having some trouble finding a rebuild.:):) Thank you for taking the time to respond.
     
  4. rtnnhazel

    rtnnhazel Member

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    Jan 12, 2008
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    84
    Location:
    las vegas
    also dont forget that reverse in 350/400/700r4 trannys is a manual gear while forward gears are hydraulic gears. that being said reverse also runs off of first gear so the tranny cannot be slammed into reverse from 2nd or 3rd. if reverse does not work and first does then it is entirely a mechanical issue and not a hydraulic issue. hope it helps a little and good luck. -robert
     

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