Torque Converter Lockup

[Buffman]

What conditions must exist for the TCU to command Torque Converter Lockup? I know on my LT1 trans Converter lockup won't occur until at least 70* Fluid temps.

I've something to the effect of 4th gear on the 4EAT, that it will stay in 3rd until it's slightly warmed up. From what I've noticed, the TC isn't locking up for at least 15-20 minutes of highway driving. Of course it's getting pretty cold outside, and obviously highway driving will greatly reduce trans temps, I was just curious as to what temperature and other factors need to occur before TCU commands lockup.

Trans Shifts fine through all gears, and when it does lockup, it's firm (not as firm as the L/UP on my LT1), and does it with no issues.

Only Code I get from the Trtans is for Duty C solenoid. Does that affect lockup? I also sometimes wonder if I have a loose connection somewhere. I had the vehicle on/off three times this morning, and the first two times, power light didn't blink. Wasn't till after the third time (still sitting in the driveway) that it started to blink...

[A1Fiddler]

Mine just locks up at light throttle on the freeway. I don't know for sure, but 15 minutes sounds like a while...

[tahiti350]

My '92 seems to do about the same as yours, takes about 15 minutes of combined driving before it will lock, but all shifts are solid, and the TC is also.

My '90's seem to lock up sooner, but also unlocks every time I backpedal and accellarate again.

Maybe it's a fix to keep the TC from locking up/unlocking like the earlier cars, based on customer response???

[Buffman]

Yeah once mine locked up it will stay locked up until mild throttle, or on decel if you get under 40mph.

[Legacy777]

With colder temps, that sounds about right. Mine would stay in 3rd for a little while when it was really cold.