Look to see if the throttle valve cable (passing gear cable) is connected to the carburetor or throttle body in the case of fuel injection. The cable must be hooked up and adjusted correctly at all times, because this controls the pressure. When you step on the gas pedal the throttle valve cable turns the transmission pressure up. This is how to make the adjustment on the cable. With the throttle wide open, the cable must be fully pulled out at the exact same time. The adjustment is made at the bracket. You must push a button in or pull a button out to move the cable housing forward or rearward. Moving the cable housing to the rear raises the pressure. Be careful, if you adjust the pressure too low you could burn the clutches.

If your transmission doesn’t shift out of first gear or shifts hard at too high a R.P.M. this doesn’t always mean you have a problem. This could be a stuck throttle valve caused by a small piece of trash. This sometimes happens after a rebuild. Sometimes the throttle valve can be unstuck without removing the valve body. Get up to about 20 to 30 M.P.H. and hit the gas pedal on and off hard with your foot. This might do the job. If that doesn’t work remove the throttle valve cable end from the throttle, with the motor at idle in park, pull the cable in and out very fast, this might work, if not the valve body must be removed by a transmission shop to be unstuck.