1995 Sierra 700R4 transmission slipping

Discussion in 'GM Powertrain' started by ccrbt5, Jan 1, 2013.

  1. ccrbt5

    ccrbt5 New Member

    i have a 95 gmc sierra with a 5.7 and a 700r4 trans i went to go in reverse and nothin happend so i put it in D and it started moving but wouldnt wouldnt shift till it got up there in the rpms unless i let off the gas need some help to find out whats wrong with it thanks
  2. Skippy

    Skippy Member 2 Years 100 Posts

    Hey, I'm admittedly not an engine guy. so take this with a grain of salt.

    I would think you might have a fluid pressure problem, caused by either a vacuum leak, a clogged fuel filter, or something like a bad modulator valve. Basically, the automatic transmission requires line pressure to shift between gears. If the pressure can't build, no shifting until high RPM (at which time the pressure is sufficiently high). Basically, check for loose or dislodged vacuum lines, and change the transmission filter if it's not been done in the last 40K miles.

    Another possibility, if you've recently had a rebuild, is that you might have an impeded throttle valve. If you can do it, get the vehicle to 20-30MPH and then stomp the gas pedal on and off lots of times to dislodge the impedance. If this doesn't do it, ask someone else, I'm out of ideas. However, if you've actually recently rebuilt this, I suspect you could just take it to the tranny shop and get them to figure it out under warranty.

    Good luck!


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