I have a 4L80e in my truck.. Last night at the track, it would not shift back into first after the burn out. I tried putting it in reverse, nuetral, and then first, and it still stayed in second...

Any suggestions? What controls the shifting at part and full throttle in our trans? Mainly from first to second, and downshidting from second to first.

 

Here is a short list. It's kinda of scary though


It could be....
broking housing
Rear band anchor pin brokin
Shift lever not adjusted or may have sliped
Front band stuck on
Lower roller assembly
center support or splins brokin
The case damged near center support


I Pulled this info out of my ATSG manual.

Does all other geats and tcc work like they should??????

 

Of course first you need to make sure the PCM is commanding first....

 

Oh man, that is scary. lol

It only happens on the burn out. Every other time, when I come to a stop from various mph, it will downshift back to first. All the other gears seem to be working fine.

My first 4L80E did the same thing. I would get 2 or 3 good runs in and then the runs after that, it would get stuck in second on the launch.

 

So when you put a load on it with-out rolling it goes into second?

 

I can put a load on it and it will go into first.. The condition only happens after a burnout where the trans goes through 1st and 2nd. For some reason, it cant make its way back to first.

I checked the linkage on the trans.. It does go into first gear when the lever is shifted into 1 on the steering column. I wonder if there are some elctronics that would prevent it from going into first.

 

after i put mine back in a few weeks ago it would only go into second, the electrical connection for the park neutral safety switch was not in all the way..found out buy my builder that if that connection is not good there the pcm commands second gear

 

Good information, I am going to need to check this out. I will report back.

 

never reported back..guess it didnt work

 

Okay.. TTT. lol

Bill let me use HPTuners when we were in AZ to log. I am going to see if he can post up the scan.

I was manually holding first gear when doing a burnout and the trans was shifting between first and second. If you look at the log, I do not think the TPS changes.

Bill - Can you post it up for me?