won't shift into second gear at wide open throttle. Part throttle does fine.
Mark

 

I have seen this with 2 different built 80's, but it is a little different.

From a dead stop it will shift fine, but if it down shifts into first, it will not shift out of it @ wot.

Each trans was built by different a individual.

Let me know what you find.

 

mine will shift fine from light to pretty hard throttle but not wide open. it will down shift from 3rd to second under heavy throttle. PCM is commanding it to shift but it isn't cooperating.
Chuck and Rick are going to trouble shoot it today.
Mark

 

Now that you mentioned commanding, my tranny keeps on locking the converter, even though I comand it it not to.

 

Mark I'm glad to hear you got the truck back, hopfully all the kinks will be worked out soon and you will just get to enjoy it!

 

i had this happen in my 4l60e. it was my fualt though the accumilator i think it is was not tight and would leak at wot but shift fine at part throttle.

 

I don't have the truck back, I just took it to the photo shoot.
The first 4L80 wasn't vacuum modulation and it shifted fine into second under full throttle, but second still took a dump on me, so this time around we went vacuum modulation and now it won't shift into second under full throttle but will at part throttle.
Mark

 

Not to sound like I'm questioning anyone, but could the problem be in the shift points. I know with some of the much higher power applications you have to set the shift points 1000rpm or so lower than what you actually want it to shift at. For example if you want it to shift at 6k you have to set the shift points for 4800rpm or so. If I recall correctly even Parish had that problem with his level V 80E.

 

I will run it by Rick, but the first 4L80 shifted when it was suppose to. I am only running 700ish HP right know.
Keep the ideas coming.
Thanks,
Mark

 

I was trying to find that post where he was talking about that. I've ran into that with others, but that one just comes to mind since he was running the same trans.