misterp Posted January 17, 2007 Report Share Posted January 17, 2007 (edited) I've noticed in the last couple months that first thing in the morning my torque converter clutch won't lockup until the truck warms up a little, should I be worried? Is this a PCM programming thing, or maybe something in the valve body? The fluid & filter are fresh... I definitely have 4th gear (I checked) but the clutch won't engage until I've driven the truck for a few miles, then it behaves normally. Any guesses as to what the reason might be? Mr. P. Edited January 17, 2007 by misterp (see edit history) Quote Link to comment Share on other sites More sharing options...
misterp Posted January 17, 2007 Author Report Share Posted January 17, 2007 And what the hell is a google Tundra ad doing in my post?! Quote Link to comment Share on other sites More sharing options...
rivierakid55 Posted January 18, 2007 Report Share Posted January 18, 2007 I've noticed in the last couple months that first thing in the morning my torque converter clutch won't lockup until the truck warms up a little, should I be worried? Is this a PCM programming thing, or maybe something in the valve body? The fluid & filter are fresh... I definitely have 4th gear (I checked) but the clutch won't engage until I've driven the truck for a few miles, then it behaves normally. Any guesses as to what the reason might be? Mr. P. same thing with me mister p. ive noticed that since its really cold mine wont lock up either until my trans temps get above 100 degrees or so. tried starting out in both 3 and drive and same thing. talked to my tranny guy and he said very normal so that's what im going with. Quote Link to comment Share on other sites More sharing options...
StealthSS Posted January 18, 2007 Report Share Posted January 18, 2007 I know it used to be a ricer feature, but didn't know our trucks did it. Quote Link to comment Share on other sites More sharing options...
PladdPezzPunk Posted January 18, 2007 Report Share Posted January 18, 2007 you should also notice the shift firmness down and the points higher. this is a cold start routine. once the tranny gets to the programmed temp, it will respond normally. It really protects the tranny just as the rich start protects the engine. Quote Link to comment Share on other sites More sharing options...
zippy Posted January 18, 2007 Report Share Posted January 18, 2007 (edited) He's correct, the tcc programming is set to lock in the tcc at around 140º or so. This is to keep high load off of the cold engine and keep it a smooth feel since some engines are rougher running when cold. The shift points are also extended when cold to help try to warm the engine up quicker. Add: If the transmission fluid temperature is less than 17°C (62.6°F), torque converter clutch (TCC) operation will not occur until the transmission fluid temperature is greater than 20°C (68°F). Just a bit of info I just found while looking this subject up to add to it. Edited January 18, 2007 by zippy (see edit history) Quote Link to comment Share on other sites More sharing options...
Luaderdale SS Posted January 18, 2007 Report Share Posted January 18, 2007 Dang, you guys are knowledgable! good info Quote Link to comment Share on other sites More sharing options...
SS_bnoon_SS Posted January 19, 2007 Report Share Posted January 19, 2007 Yeah, I found out about the tcc lockup temp control when I first got HPT. Sucks. In my old '86 TA, using GMECMEdit, you could set the enable temp and I could lock it up when ever I wanted to. Makes sense for me since I only drive short trips to work and never haul anything, and the trans never gets to lockup since it's never warm enough to lock it until summer time. I get 9 MPG right now in town when I drive only back and forth from work to home. 9 MPG!!!! WTF?!?!?!? Quote Link to comment Share on other sites More sharing options...
Bowtie70SS Posted January 20, 2007 Report Share Posted January 20, 2007 I noticed that too, especially since winter has hit here in Ohio. I figured it was some kind of feature to get the trans up to proper operating temperature. Mr P you put a thermostat in your transmission line correct? I'm thinking that I may need one since my trans cooler is a giant Setrab oil cooler and my trans temps here lately haven't been above 140. Dave Quote Link to comment Share on other sites More sharing options...
misterp Posted January 20, 2007 Author Report Share Posted January 20, 2007 (edited) I noticed that too, especially since winter has hit here in Ohio. I figured it was some kind of feature to get the trans up to proper operating temperature. Mr P you put a thermostat in your transmission line correct? I'm thinking that I may need one since my trans cooler is a giant Setrab oil cooler and my trans temps here lately haven't been above 140. Dave Yeah it came with the Long cooler. I'm not exactly happy with my trans thermostat, my tranny temps are also pretty cold right now but eventually if given 20-mins or so it will warm up to 180-ish and that's too warm for my taste, I'm thinking of cutting a coil out of the bimetallic spring or otherwise modifying it to hold temps at 155-160, the tranny seems to grab best at that temp. You might check the Earl's catalog and see what they have, I bought a huge one for engine oil cooler on a past vehicle, maybe someone makes smaller ones that can be set to 150-degrees??? Mr. P. Edited January 20, 2007 by misterp (see edit history) Quote Link to comment Share on other sites More sharing options...
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