What would cause the 1-2 shift valve to stick ?

SCHMITTY

SCHMITTY

Not enough time
Joined
Jun 20, 2012
Messages
1,201
Truck is an 05' with 1k miles on rebuild. Started acting up- would not drop down into 1st and was drawing out shifts. Manual first works if you go into nuetral and then manual 1st. Line pressure from acumulator port was 90 psi at idle and at 55 mph, but when I let off the throttle it would jump up to 145 psi. Gov pressure was at 90 psi no matter what speed I was going. I then pulled the pan and it was spotless inside but I did notice the kick down band was a little loose - 3/8" between the apply lever and servo.

i found that the 1-2 shift valve was stuck. The bore and the valve looked good and everything was installed correctly I just want to avoid sticking the valve again.

Any ideas ? Also the gov pressure sensor was not seated all the way.

Thanks
 
Anybody? Would a poor fitting gov solenoid cause it ? I found the current one to be a little loose. I modified the metal bracket to hold the solenoid in tighter. It will won't go back into first when I come to a stop though. Trans works great besides that.
 
are you running OEM or what? i went to GM solenoids and never looked back. for me, contamination was always the issue.
 
It has the TV motor. I only have 1k miles on this one and it looke clean, I sprayed it down with brake clean and some air. I will try the electrical testing on the connectors before I pull the pan again.
 
So would the gov solenoid cause the actual valve to stick in the bore ? It is the upgraded bw solenoid.
 
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