It only happened a couple of times, but when in the process of warming up, my 92 RS went in and out of lockup. It did not do this when it was warmed up. Any input would be appreciated.

 

You didn't explain in enough detail what you mean, but if it is intermittently randomly unlocking while it should be locked, the tcc solenoid plastic "neck" may have cracked on the molding seam. I had this happen on mine. $25 bucks for a new tcc solenoid fixed it.

 

I was driving when the temp gauge was just showing some temp, and enough temp for the tranny to lock up. it only happen twice, but at this threshold, it locked up, and went out, then in,,, out and in, kind of up and down. Then it was ok. It hasn't happened since, but it may again. This is my best description. Where is the solenoid located? I would be willing to replace it for that price.

 

yup, sounds like the lockup solenoid to me. its in the trans pan. so youll have to pull that off. youll need a new gasket, may as well do fluid and filter while youre there... clean the magnet off too.

 

I'd make sure the ECM isn't commanding it to unlock before diving into the pan.

 

Would a diognostic machine know if the ECM is doing it and not the solenoid? I just did a filter, fluid, and gasket in June, but I will do what is necessary. I did change the TPS, before this happened. It did it after the TPS change. Probably a coincidence. It hasn't done the in and out of lock up for over 2 weeks now, and I have been driving it regularly.

 

If it happens again, put a test light between pins A and F of the ALDL and note when the light turns on and off.

 

Most likely causes of intermittent lockup are the brake switch, CTS and the TPS. It's usually the wiring to the CTS that opens and confuses the ECM into thinking the engine is cold. A TPS that randomly varies the voltage signal confuses the ECM into thinking the throttle is changing drastically, but you may be able to rule that out.

A scanner hooked up while you drive will tell you whether the ECM is commanding unlock. It will also show the data the sensors are sending as it commands unlock. If it's unlocking while the ECM is still commanding lock you'll know to look elsewhere.

Sometimes the CTS will just be at the threshold temp for lock then the thermostat opens and it jumps back down a few degrees.

 

I just changed the CTS also. Are you saying the wiring to the CTS could have a bad connection? By the way, I had the break switch on my Silverado cause this. I held the break out with my foot and it stopped. Interesting you mentioned this.

 

The wiring could cause this, but before going about replacing stuff jumper the pins like Apeiron pointed out. See if the problem's on the ECM side or not.

 

Naf is spot on I had the same damn problem. CTS wasn't setting any codes either. Checking it out how Apeiron is suggesting will help determine if it's possibly the cause.

It ended up being the connector for the CTS. Ordered a new one from summit for next to nothing and spliced it in place of the old one.

It's been a while but I'm almost certain it's this part;
http://www.summitracing.com/parts/PCO-5615PT/

 

Where did you get the connector Doom86? I could call the dealership, but they don't stock many parts like this, so I am reluctant to call. I bet the connector is the same on many GM cars. Maybe I could let it soak in WD 40 to remove any oxidation.

 

There should be a tan/blk wire going to the aldl connector under the dash. Grounding this wire should lock the tcc. Here's a couple pics of what happened to my tcc solenoid. The solenoid itself still worked but the cracks would allow fluid to leak out of the converter clutch allowing slippage. Normally fluid passes through this solenoid and when it energizes it blocks off the passage to allow pressure to build to lock the converter. The last pic is where it is located. It's removed in the pic.

 

I am assuming that is the new one next to the cracked one. It's hard to see in the tranny pic the solenoid. I'll take note on where it is.

 

It's not installed in the pic.

 

I thought it looked damn small.

 

I linked it in the post but will again.

http://www.summitracing.com/parts/PCO-5615PT/

First make sure the ECM is making it happen as Apeiron suggest.