Think my TC is bout done

[Philv]

Every morning when I leave for work, I get on the highway and it takes about 5-8 miles before my trans goes into OD. I've noticed once it warms up some it works better, but I think it's just tired. How hard is it to rebuild these transmissions? I am an ase master diesel tech, but I'm not familiar with autos much. Mainly manuals.

 

[TheBac]

Mine does the same thing in the colder months. I dont worry too much about it.

 

[Philv]

Mine does the same thing in the colder months. I dont worry too much about it.

when I leave for work, it's between 35-55°. So not shifting into OD at first is normal at that temp?

 

[TheBac]

Not sure if its normal or not, but I never asked anyone about it b/c the trans worked just fine after it shifted into OD.
I figure it had to do with trans temp/fluid viscosity.

 

[clrussell]

Yes it’s normal for older trucks. Trans needs to see a certain temp to go to overdrive

 

[Chevy1925]

Um.... you guys all get “OD” even when cold, the converter just won’t lock till a certain temp is reached. What you see/feel is lack of TC lock and then it finally locking

 

[duramax on fire]

Mine hates anything below 70 like me lol.

Mine does the same around 40 temps

 

[WVRigrat05]

Like janes said it’s going into 5th, the converter just isn’t locking, my truck idles 5-10 minutes before I drive it

 

[joshd472]

My tc on my LLY wouldn’t lock until the trans reach 80 degrees.

 

[clrussell]

Um.... you guys all get “OD” even when cold, the converter just won’t lock till a certain temp is reached. What you see/feel is lack of TC lock and then it finally locking

Shit I knew I was wrong

 

[Philv]

Lol thanks guys. I'd idle it, but my landlord lives on site. Last thing I want to do is piss him off with noise and smoke.lol

 

[TheBac]

IMO its not lockup. Not with that much RPM reduction when it does hit.

But....whatever. Not gonna argue it. I never invested the time to properly/completely understand these transmissions.

 

[Chevy1925]

Just drive it. Allison does it to help get the trans up to temp. Wont hurt anything to drive it that way. You can always adjust the temp lock up in the tcm if you want. Mines at 50*

 

[Mike L.]

Normal on older trucks. The TCM is slightly pulsing the converter clutch on when cold. Converter locks at about 101F or ther abouts.

 

[Philv]

Normal on older trucks. The TCM is slightly pulsing the converter clutch on when cold. Converter locks at about 101F or ther abouts.

Thanks Mike. Sometime here soon I'd like to pick your brain about trans options. I know I'm gonna have to rebuild it soon.