Who can get me a fluid circuit diagram for TCC lockup? They might be found in the GM service manual, but I don't have one (yet). I have a feeling that the TCC valve in my trans is a little sticky, seeing as how it now locks in First at a dead stop, and then releases as I accelerate.

Also, if the valve IS dirty, can I clean it somehow, say, when I install a shift improver kit? If the TCC doesn't work afterwards, I won't be much worse off because it already works when it wants to.

 

I've got one for an earlier revision of the 700R4, but it changed in 1987. IIRC it's pretty simple in the later ones, apply pressure to the TCC comes from the 2nd gear circuit, but is exhausted by default. When the solenoid is energized, the TCC checkball blocks the exhaust port and the TCC locks.

 

<img src="http://www3.telus.net/~crussel/tcc_applied.gif">
<img src="http://www3.telus.net/~crussel/tcc_released.gif">