On my drive this morning to work, my torque converter didnt lock at all. I let my truck warm up before i leave everyday since its freezing right now(20) and by time im out of my subdivision usually, it will lock up at higher speeds(45-50). Well, this morning it wouldnt lock up at all, no where on my 40 minute drive did it lock up. It doesnt feel as if it is slipping or anything like that, it shifted into OD but never locked up. I checked the trans fluid when i got to work, it is still full. What can be the cause? Converter toast? I dont want this thing to tear apart a trans too, i wouldnt be able to afford both. Truck is a 2002, 4.8, 2wd. Ill have to search later when i have time but figured i would post to get some responces. Thanks.

 

Possible causes... maybe it didn't get warm enough with the lower temps. Missfires will prevent lock, sticky/made brake light switch, not reaching the lockup speeds and throttle positions required, defective or sticking TCC solenoid, blown TCC seal on output shaft.

 

Well i drove the truck on lunch break, after about 5 minutes of it warming up, the torque converter locked. So what gives? I wonder if it didnt get warm enough because it was 15 out this morning but after 40 minutes of driving, I would of thought everything would of warmed up. I was up to speed. Constant 55 should of done it. It usually locks under light throttle between 45-50. Yesterday, it was 50 in the morning, rainy then dropped to about 15 that night. Could this of made a sensor/solenoid not function properly?

 

Willing to bet it just didn't warm up enough. At one time I lowered my lockup temp limit (not recommended), and on 28 - 32 degF mornings, my truck would take ~15 minutes warm that fluid, and I'm running through a stock radiator @ 70mph (interstate). RPMS (if memory serves) were ~2700 before the lockup (w/ 4.10s). BTW... I have a 160 T-stat. Hell, during my daily 50-mile, one-way commute (given that ambient temp outside), my truck barely reaches 180 for the coolant temp (theoretically, that's low too). I'll have to look at HPT, and see what my setting is.

 

Well, i dont really know. It just kind of freaked me out this morning.... i guess i got a bit paranoid. Hopefully its nothing serious and i dont see it happen in the future. On my drive home, everything was fine. Truck ran like normal.

 

Do you have a trans. temp. gauge? Cold days can take my truck up to 10+ miles to lock up. I believe stock PCM will prevent TCC lockup until trans. temp. reaches 75*F. My trans temp gauge reads off the OBDII port and I can watch it climb on the highway and the moment it reaches 75*, I feel the TCC lock up. Do you have a larger than stock trans cooler on it?

 

Nope, no trans temp gauge. I have nothing done with the trans so far, i have servo's waiting to go in, so no larger than stock trans cooler.

 

I've been having the same problem. Once in a while it wont lock at all. I have a temp guage and it's allways up to temp some trips it wont lock at all. Other trips it locks perfect. I'm going to check my brake light switch, I'm hoping thats the cause or else I,m thinking some thing in the tranny may be stuck. Any more Idea's. It always locks when I'm at my tuners house, but always screws up the next day.