hi, please correct me if im wrong,is the t.c.c. connector on the drivers side? 3wires green,pink.tan maybe? if im right and my car has a older 350 & a350 tranny, later model dist. no more e.c.m would i need to worry about this not working?is there anything wrong doing this ? i dont plan on using this vec.much on the highway wher a locking t.c. might give me a little better m.p.g. thanks to anyone who can answer any of my questions. carl

If it does have a turbo 350 it doesn't have a tcc. Identify your transmission so you know what you have for sure.

If it does have a turbo 350 it doesn't have a tcc. Identify your transmission so you know what you have for sure.


I beg to differ. I have an '84, with a Turbo 350, that has the Lock Up feature. I bought the car, from my Uncle, who was the original owner, and there has never been any trans change, replace.

When I replaced the engine with a 350, and went to a Mallory distributor, naturally I lost the ECM and the lock up did not work. I took it to a trans specialist (re-programs, builds race PG's, etc.) who re-did the lock up for me, attaching it to a toggle switch. Other than having to turn it on, it works just like it did before. 8)

dcar,please tell me,what happened when you removed the e.c.m. & you used the car?any more info. on the togle switch? thanks carl p.s. im no expert but ill look again it looked to me as a turbo 350 oil pan shape.

Identify your transmission so you know what you have for sure.

That is the reason I added this statement. In case he had a 350c or something else had been installed. I still maintain if he has a 350 he does not have a lock up. If it has a lock up it is designated different.

464elky, i know little about g.m. tranny identification so please bare with me. the pan shape is right on, the bolt pattern on the pan is same as the t. 350 and the color of the 3 wires matches and the location of the plug on the tranny is where it is described,so i need to figure out something also the previous owner said it was a t.350. all i know is that the e.c.m. is now gone and what is going to happen to the lock up mode? after i get it cleaned off ill see about getting some numbers all i can see now is on the case next to the tail #jbj170756 but i didnt have my glasses on thanks carl

dcar,please tell me,what happened when you removed the e.c.m. & you used the car?any more info. on the togle switch? thanks carl p.s. im no expert but ill look again it looked to me as a turbo 350 oil pan shape.


Nothing happened. It just shifted 1st - 2nd - 3rd. No lock up. That is why I took it to the trans guy - I don't know much about them either - but, he does. He wired the lock up, to a toggle switch (it's just a regular 2 position on/off toggle), which is right under my steering column. When I am going to be on the interstate, I just turn it on, and it will go into the lock up. When I am going to be just running around town, I turn it off. .

1980 to 1984 GMC's came with a three speed auto/w tc lockup.. I have an 82 caballero with lockup tc. Had an 84 GMC pu with same trans it locked up at 34mph. I changed the solonoid switch six times before I got one that locked up at 47mph. THE PARTS DEALER SAID THAT YOU JUST HAD TO TRY THEM UNTIL YOU FOUND THE ONE YOU WANTED.:let_it_all_out:

Nope,as you surmised ,only fuel economy will be affected. In fact earlier Cadillacs would allow thier converter clutches to slip a little to minimize "chuggle" caused by rough engine inputs. Don't know what they do now.

If it does have a turbo 350 it doesn't have a tcc. Identify your transmission so you know what you have for sure.

We have already identified his transmission as a TH-350C, it has the convertor lockup feature.

The electrical connectors on the TH-350C, TH-250C, and TH-200C are for the lockup torque converter clutch. Note that the 'C' suffix on the transmission model signifies it is a lockup torque converter model (i.e. TH-350: no lockup, TH-350C: lockup). The reverse light switch is part of the neutral safety switch assembly. The same switch is used to tell the ECM that the vehicle is in park/neutral as opposed to in gear (idle control).

www.bmracing.com/bmracing/installation_instruction/9500475-08.pdf