torque converter control

[like2drive]

Mine is an '81 stock w/automatic 350. I've had the trans. rebuilt, but I've always had a problem with the torque converter not locking up half the time when I want it to...say like on a long trip. Sometimes I can cause it to engage by driving real fast (80-90)for 5-10 minutes to where the temperature gets up to 200 degrees, then stop and start over, and it "might" go into lock-up for the duration of the trip. I can go on a 300 mile trip, and it may never go into lock-up. The key is the temperature that tells the almighty computer to engage lock-up. Does anyone have a fix for this? Every thing runs good. Seems like I've been told about a direct switch to engage, but you have to remember to disengage when coming to a stop. thats ok with me! Or a trans. mechanic told me that there was wiring available that you could dial in what speed you want the lock-up to engage. (I don't think his idea was meant for an '81 w/computer....but well, I am the one asking!!
I'm thinking someone like TPI or Painless could have something...Thanks...

 

[Tomlin]

Torgue Converter Lockup

Well, I see no one else has replied to you so I'll give you this bit of info and I hope it helps. Some years years ago my TC would not lockup. It would shift from 1st to 2nd to 3rd in seconds and the engine would be bogging at 35 mph i 3rd. I took my 81 to our area Vette dealer and had the Vette mechanic look at it. He remembered a tech service bulletin about this so he dug it out and according the GM the problem cropped up occasionally is some transmissions and the cure was to disconnect the computor from the transmission. This was done and I haven't had a problem since. That was 5 years ago. The mechanic also indicated that it was important to keep the proper thermostat in the cooling system since temperature of the trans fluid is important.

I'm not sure this is the same problem you have but mabe this will give you some insite.

Tech Service Bulletin # - 83I23
Tech Service Bulletin Issue Date - Dec. 1982
Tech Service Bulletin Title - TCC engages at incorrect speed - All gas engines

Tom

 

[Yoda]

Tom,

It's good seeing you here.. You may not post a lot, but when you do it's worth listening too

How's that engine running now days :J

Bud

 

[Tomlin]

Torque Converter

Hey Bud, thanks for the kind words. Got the engine all cleaned, back in and she's runnin fine.

Tom

 

[Rudzvetz]

The converter lockup uses a few things that you could check to see what is going on. I'm thinking that your operating temp is OK because the only temp that would affect converter lockup (with the exception of fluid viscosity changes that would affect internal transmission pressure) is the engine coolant temp that is picked up at the ECM coolant temp sensor. The vehicle speed sensor lets the ECM know when the car is up to 45 MPH. There is no lockup before that. Then the converter lockup is dependent on the brake switch, the lockup selenoid inside the transmission and the high gear pressure switch in the trans. There is also a TCC test port in the fuse block that you can wire a light to that will tell you when the computer is locking up the converter.


-Justin