4L80E Transmission tuning question
 

My 4L80E has been having an issue with WOT shifting from 1st to 2nd. It likes to bounce off the rev limiter/fuel cutoff or I have to let off the throttle a little at the top of 1st to get it to shift. Not really the best plan when running someone from a stop light.:angel: It has done this since install and the tune is new as well since I swapped to the 80E from a 60E.
I backed the 1-2 shift point down from 6000 to 5800 and it didn’t seem to help. I can’t get to it right now (see avatar location) but I am wondering if I dropped the shift rpm to say, 5500, would that help? Do you guys with the 4L80E have an issue with a long over run in rpm’s from 1st to 2nd? I have the shift speeds set low so I know that is not the issue.
I’m trying to make sure it's not a tuning issue before I pull the trans and dig into it.
It is a “built” 80e with a HD shift kit. The 1-2 part throttle shift is waaaay too hard as well. I think the shift kit was setup a little extreme. I don’t know if that would have anything to do with the WOT shift though.
Go……..

Your efi right? Have you bothered dc_justin yet? or kbracing? What is the shift speed in the WOT setting AND the 100% shift speed in the p/t shift table?

Yes, EFI.
No, Have not bothered them ...yet
I was working the issue when I got orders to Iraq and left 4 days later:eyes:
I will be back in 40.33 days/967.98 hours. Not that I'm counting:D

I dont have my laptop with me but I remember lowering the 100%TPS table. I will have to grab my laptop tomorrow, I could even load the tune for you. You an EFI user?

https://www.performancetrucks.net/fo...5&d=1197489984
Try this

I am not an EFI user, I have issues navigating around in it. LOL MAC vs Windows to me. But, glancing at that tune, your p/t 100% shift is at 35mph and your WOT mph is at 25MPH. My 80e makes it to 50 to 55mph before I shift (6200ish). Seems your speed settings should be okay, it doesn't matter but zero out your WOT shift speeds just to get them out of your way, just so you only need to worry about one set. You aren't running SD, any MAF codes? any codes? I don't understand EFI's pressure tables LOL You have crazy numbers in there, I am sure they are right, but they don't make sense to me.

Did you zero out your shift times to disable the adaptive shift? You need to because you have a shift kit.... From what I have read, if you don't the computer will see that your shifting faster than the programed shift time and start lowering the tranny pressure...

he had all "zero's" in the 1-2 desired shift time row.

Sorry I did not notice he posted the tune... Looking at your tune your Part-Throttle shift MPH is at 56 in the last two cells (93.8% and 100%).. Given your tire size (31.86) and Gears (4.10), so that translates into 56MPH @ 6000RPM... IMO this is why your hitting the rev limiter.... Lower the last to cells in the part Throttle table by ~5 MPH, then you should be good to go!

Edit: Sorry about this, but the new version 7.5? converted all the numbers wrong when I installed the software up at work....

that's what i was looking for but I converted differently. I only have the demo version and I get kph and then convert to mph. And then got a way smaller mph.Cool, I agree if those numbers are right.

Which MPH did you get that was smaller? MPH based off of tire size and rear end and tranny gear or the values loaded into the table?