Bad TCC solenoid or converter?

[toomanymodz]

I local Buick enthusiast brought his 87 over to my place today complaining that the transmission isn't shifting correctly. We went for a short drive around the block and this is what I observed:

The converter locks as soon as the tranny shifts into 2nd gear. The converter stays locked, at any speed, in any gear, except for 1st gear, which then it unlocks. Also, if I lift up on the throttle then apply throttle again, it stays locked the whole time. Also if I stay on the throttle while driving and press the brake at the same time, it stays locked.

Only when I slow down and the tranny shifts back into 1st gear does it finally unlock. Ideas?

 

[aminga]

Sounds like the TCC, Unplug the plug on the side of the trans and try it again.

 

[MeanBuicks]

That may not even do it. A common failure mode for the solenoid in the 200-4R is that the check ball gets stuck in it preventing it from disengaging the TCC even when it's de-energized. When the trans downshifts to first, the internal fluid pressure signal to the solenoid is relieved and the converter clutch releases.

 

[toomanymodz]

So the check ball is part of the solenoid? Do you think that if I change out the solenoid then the issue will be resolved? That sounds like an easy fix.

 

[BuickMike231]

Definitely sounds like a TCC solenoid. When you are sitting at a red light or anything like that where you are in drive but stopped on the brakes, does it try to push through the brakes when still? Your description sounds very close to what I experienced and it was my TCC. Hope you get it sorted out!

 

[toomanymodz]

I didn't notice it stumbling or pushing at idle. Only when the tranny was in 2nd gear (or higher) did it lock up. Maybe I should have him disconnect the connector and drive it, just to see how it behaves.

 

[MeanBuicks]

Yes, the checkball is part of the solenoid and the solenoid is an easy thing to replace.

 

[toomanymodz]

Awesome. Thanks for the input. Looks like the solenoids are cheap to buy, around $15. He's going to love the good news.