200R4 Transmission TCC, 4th gear pressure switch, and temp question

[t-topflyer]

TH200-4R TCC Solenoid Transmission Problem



Using tips from the article at the link above, I've been trying to narrow down a problem with 4th gear in my 200 R4 transmission. I've had TCC problems with another turbo buick in the past which I replaced the TCC solenoid and the problem resolved. This is a slightly different problem and I need some advice before I continue to go about fixing it.



This problem is in 4th gear. The TCC engagement/disengagement seems to have a mind of it's own, and does so sporadcally around 55-60 mph and above. I just replaced the TCC solenoid, and while it does seem to stay engaged longer, it still doesn't seem to function exactly like it should. The car has an aftermarket transmission cooler and runs constantly between 160-170 degrees, so I don't know if the operating temp has anything to do with it. After replacing the solenoid, I don't know what system or systems I should look at next. The ECM, 4th gear pressure switch or ?? The internals in the transmission looked great. Any tips would be great. thanks

 

[mikestertwo]

Explain "sporadically" Do you have a scan tool?

 

[t-topflyer]

Explain "sporadically" Do you have a scan tool?

Got a scan tool. Sporadically meaning that you never know when or where above 55-60 mph it's going to happen. It is not consistent in it's behavior.

 

[mikestertwo]

Does the scan tool show the converter locking normally? If so, check your brake switch. The TCC gets it's power through the brake switch. It could be missadjusted or bad.

 

[Lee Thompson]

next time it does this

Take your left toe and pull up on the brake pedal.

 

[Sal Lubrano]

There is a switch at the brake pedal which unlocks the converter when the brake is pushed. If the switch is broke or mis-adjusted it will cause your problem.

 

[t-topflyer]

Does the scan tool show the converter locking normally? If so, check your brake switch. The TCC gets it's power through the brake switch. It could be missadjusted or bad.

There is a box on the powerlogger screen next to "TCC locked", but in the last few runs since I've noticed the problem, I don't recall ever seeing the box with a check mark in it.

Just to clarify, when should and when shouldn't the TCC be locked?

When the TCC does engage in 4th gear, I can sometimes tap the brake pedal, then let off and it does function as normal. But probably 80-90% of the time, I never feel the TCC engage, and if it does it is usually brief, then comes back out for no apparent reason (w/o regard to brakes being applied, change in engine/tranny load etc.)

How can I check and see if the brake switch is out of alignment, and where exactly is the switch?

 

[t-topflyer]

I never thought the solution would be so simple. I pulled out on the brake pedal and heard 2 clicks. Turns out the switch was out of adjustment because it functions just fine now. Thanks for the help!