c4 with no reverse(sorta)

Discussion in 'Transmissions' started by my70mav, Jul 9, 2011.

  1. my70mav

    my70mav Member

    Joined:
    Apr 9, 2009
    Messages:
    616
    Likes Received:
    0
    Trophy Points:
    88
    Location:
    Elk Grove,ca
    Vehicle:
    69.5 maverick
    I finally tried to drive the car (in the drive way) with the rebuilt c4 to put it in the garage and I get nothing. However, when we were pushing it backwards I started it and put the car in reverse,gave it the gas and it wanted to go foward. I have not driven it to see if it shifts into any other gear. Fluid is full best I can tell since my driveway is at a pretty good angle. Any ideas?
     
  2. my70mav

    my70mav Member

    Joined:
    Apr 9, 2009
    Messages:
    616
    Likes Received:
    0
    Trophy Points:
    88
    Location:
    Elk Grove,ca
    Vehicle:
    69.5 maverick
    The fluid level is good and I tried loosening the bands to no avail. Next I will try the reverse piston seal and if that doesn't work then I will drop the pan and make sure the studs that hold the band haven't fallen off. The trans sat around over a year before being adjusted.
     
  3. my70mav

    my70mav Member

    Joined:
    Apr 9, 2009
    Messages:
    616
    Likes Received:
    0
    Trophy Points:
    88
    Location:
    Elk Grove,ca
    Vehicle:
    69.5 maverick
    So I pulled the pan and valve body to air check the clutches like thid video



    It all checks out like the video. I am at a bit of a loss as to what to do now.Any ideas?
     
    Last edited by a moderator: Aug 3, 2014
  4. PaulS

    PaulS Member extrordiare

    Joined:
    May 3, 2004
    Messages:
    4,858
    Likes Received:
    11
    Trophy Points:
    0
    Location:
    Seattle area
    Vehicle:
    1966 Mustang, 1972, 73, 73 and 73 Mavericks
    did you fill the transmission with the engine idling in Park?
    Have you checked it since?
    Who rebuilt it? will they look at it to solve the problem?
     
  5. my70mav

    my70mav Member

    Joined:
    Apr 9, 2009
    Messages:
    616
    Likes Received:
    0
    Trophy Points:
    88
    Location:
    Elk Grove,ca
    Vehicle:
    69.5 maverick
    I did fill with it running in park. No change but the foward clutch didn't "thump" as much as in the video. I am the one who rebuilt it, I have done several gm transmissions but this is my first c4. I have to goto Portland this weekend but if I can't figure it put by the following weekend I am pulling it out.
     
  6. PaulS

    PaulS Member extrordiare

    Joined:
    May 3, 2004
    Messages:
    4,858
    Likes Received:
    11
    Trophy Points:
    0
    Location:
    Seattle area
    Vehicle:
    1966 Mustang, 1972, 73, 73 and 73 Mavericks
    The @1 mistake most people make with their first C4 rebuild is not replacing both seals for both clutch packs. there is one on the apply piston and one on the center post of the drum. When you air test use a regulator set at 40 -60 psi. If it is sealing then you will hear it with no leakage.
     
  7. my70mav

    my70mav Member

    Joined:
    Apr 9, 2009
    Messages:
    616
    Likes Received:
    0
    Trophy Points:
    88
    Location:
    Elk Grove,ca
    Vehicle:
    69.5 maverick
    I tested with 25 psi and heard leakage on everything
     
  8. PaulS

    PaulS Member extrordiare

    Joined:
    May 3, 2004
    Messages:
    4,858
    Likes Received:
    11
    Trophy Points:
    0
    Location:
    Seattle area
    Vehicle:
    1966 Mustang, 1972, 73, 73 and 73 Mavericks
    If you got leakage then there is a problem - were all four sealing rings for the clutch packs replaced?
     
  9. my70mav

    my70mav Member

    Joined:
    Apr 9, 2009
    Messages:
    616
    Likes Received:
    0
    Trophy Points:
    88
    Location:
    Elk Grove,ca
    Vehicle:
    69.5 maverick
    As far as I can remember, I will tear it down in a week or 2 and see where I am at with it.
     
  10. my70mav

    my70mav Member

    Joined:
    Apr 9, 2009
    Messages:
    616
    Likes Received:
    0
    Trophy Points:
    88
    Location:
    Elk Grove,ca
    Vehicle:
    69.5 maverick
    Finally took it to a local shop and for $300 :dizzy: they gave the trans a once over. Turned out to be a missing plug in the valve body, trans works great now.
     

Share This Page