4L80E swap issues
08-23-2011, 07:01 PM
#1
4L80E swap issues Im sure this is something simple but here goes
Engine swap, 6.0/4L80E, having problems shifting. Has a rough tune, just testing the various engine and trans functions prior to the final dyno tune
Had a harness pinout problem from a faulty diagram that gave P0740 and P0785 codes. Swapped R2 BRN for B79 (empty) and the codes are gone but symptoms remain
No first gear, feels like its starting in 3rd and freespins quite a bit before moving. Will not downshift using throttle. Coming to a stop it feels like the TC is locked and wont unlock causing stalling. Hitting the brakes doesnt seem to help. I know the brake switch is supposed to force unlock. Might be something else though
Manually selecting 1st, feels like 3rd
Manual 2nd, feels like 2nd, very solid, no freespinning
Manual 3rd, OD, feels like 3rd lots of freespin
N and R work like they should
Engine/trans have 92k miles on them. Spotless inside, trans fluid looked great coming out of it. Fresh fluid put back in at the correct level. Harness has been retested and checks out. 12v on pin E, proper PCM pins for the rest
Questions:
Does this sound like limp mode?
What will cause limp mode on a 4L80E?
Why problems with no codes?
How do you manually test the trans solenoids? Maybe one or more are sticking, it sat for approx 9 months and have a few miles on them
Engine swap, 6.0/4L80E, having problems shifting. Has a rough tune, just testing the various engine and trans functions prior to the final dyno tune
Had a harness pinout problem from a faulty diagram that gave P0740 and P0785 codes. Swapped R2 BRN for B79 (empty) and the codes are gone but symptoms remain
No first gear, feels like its starting in 3rd and freespins quite a bit before moving. Will not downshift using throttle. Coming to a stop it feels like the TC is locked and wont unlock causing stalling. Hitting the brakes doesnt seem to help. I know the brake switch is supposed to force unlock. Might be something else though
Manually selecting 1st, feels like 3rd
Manual 2nd, feels like 2nd, very solid, no freespinning
Manual 3rd, OD, feels like 3rd lots of freespin
N and R work like they should
Engine/trans have 92k miles on them. Spotless inside, trans fluid looked great coming out of it. Fresh fluid put back in at the correct level. Harness has been retested and checks out. 12v on pin E, proper PCM pins for the rest
Questions:
Does this sound like limp mode?
What will cause limp mode on a 4L80E?
Why problems with no codes?
How do you manually test the trans solenoids? Maybe one or more are sticking, it sat for approx 9 months and have a few miles on them
09-04-2011, 10:15 AM
#6
Ended up being remnants of the 4L60E tune in there
Not sure whats up with the TCC though. Ohmed out the solenoid and its fine. Pinned it to R2 and it wont lock up. Tunner commanded lockup and it didnt respond. Pull it out to manually ground it and it locks up fine
I guess it all about finding the proper pin
Not sure whats up with the TCC though. Ohmed out the solenoid and its fine. Pinned it to R2 and it wont lock up. Tunner commanded lockup and it didnt respond. Pull it out to manually ground it and it locks up fine
I guess it all about finding the proper pin
Trending Topics
12-26-2011, 06:17 PM
#9
Ended up being remnants of the 4L60E tune in there
Running into some weird issues right now myself
12-26-2011, 08:46 PM
#10
I had the PCM rough flashed from a LS1/4L60E tune to a 6.0/4L80E tune and some stuff just didnt get switched over. I made the post because i was trying to nail down all of the issues prior to dropping it off for the final tune. He said bring it on and all was remedied. The details of which I cant elaborate on much more because I had no control over the tune
12-26-2011, 09:14 PM
#11
Pocket I hope I am in the same boat as you, my calibration details say I have a 4L80E, but the damn thing stays in LIMP MODE and it worked with the TCI box.
I emailed Bill at hp tuners.
Sounds like my issue may be the same as yours.
I emailed Bill at hp tuners.
Sounds like my issue may be the same as yours.
06-13-2012, 08:55 PM
#13
On The Tree
iTrader: (82)
Join Date: Jan 2011
Location: SD
Posts: 134
Likes: 0
Received 0 Likes
on
0 Posts
Bumping this thread up as I am having the same problems also. LS1/4L80e swap and getting the P0740 and P0785 codes. My shifting problems are very similiar to those described in the first post except my 1st gear when manually shifted feels like first gear(if it goes into 1st-sometimes it won't). Everything seems to check out and ohm out fine according to the mechanic working on it. I do have hptuners myself and can get into the computer if I need to but how do I know what to look for as I have no 4L60e or 4L80e tunes to compare to? Any help is greatly appreciated as I'm going nuts trying to figure this thing out....
Last edited by BBC632Camaro; 06-13-2012 at 09:39 PM.
05-25-2015, 02:37 AM
#15
TECH Enthusiast
iTrader: (5)
Join Date: Nov 2007
Location: valley
Posts: 582
Likes: 0
Received 0 Likes
on
0 Posts
Having this problems as well after doing the 4l80 swap. I haven't done the 4l80 segment swap I don't know if this is what causing it to go into limp mode in drive or reverse. Any suggestions what to look for
05-25-2015, 07:00 PM
#17
PCM of NC has a 4L60 to 4L80 plug in adapter harness with two relays that solve the problem of running a 4L80 on a 4L60 tune. Then you just have to adjust the trans section to show the gearing on the 4L80. Anyway that was the short easy way for me.
