4L80E needs some help!
4L80E needs some help! Hello I know very little about transmissions so please bare with me.
I just got my '02 5.3 installed with a '96 4L80E in my '91 Chevy Silverado and Im having problems with the trans. It was bought used and hasnt been gone through. The tune was done by Nelson Performance and the wiring was done, checked, rechecked, and rechecked again by my friend who is a certified GM technician. He simply repinned the trans connector for 4l80e configuration. He, along with a GM tech transmission specialist say it only needs one speed sensor although all my research suggests otherwise.
Its hard to tell with a 2800rpm stall but I think the only forward gears it has are 2nd and 3rd. Reverse works fine. No 4th and no tcc lockup. I only get one shift and under light throttle it doesnt happen til about 35-40mph. It does succesfully downshift but only from 3-2.
The computer is giving codes:
TCC solenoid PWM
Trans pressure manifold switch
I took it to a transmission shop and they are scared to touch it since it is a conversion/swap. Their scanner said although it gave a code for pressure manifold switch the pms showed to be functioning. Also, a weird thing, the scanner showed a TPS angle (%) but the volt reading stayed at 0.00 at all times.
I did the mechanical part of the swap but this wiring/computer stuff is over my head. Please help!
I just got my '02 5.3 installed with a '96 4L80E in my '91 Chevy Silverado and Im having problems with the trans. It was bought used and hasnt been gone through. The tune was done by Nelson Performance and the wiring was done, checked, rechecked, and rechecked again by my friend who is a certified GM technician. He simply repinned the trans connector for 4l80e configuration. He, along with a GM tech transmission specialist say it only needs one speed sensor although all my research suggests otherwise.
Its hard to tell with a 2800rpm stall but I think the only forward gears it has are 2nd and 3rd. Reverse works fine. No 4th and no tcc lockup. I only get one shift and under light throttle it doesnt happen til about 35-40mph. It does succesfully downshift but only from 3-2.
The computer is giving codes:
TCC solenoid PWM
Trans pressure manifold switch
I took it to a transmission shop and they are scared to touch it since it is a conversion/swap. Their scanner said although it gave a code for pressure manifold switch the pms showed to be functioning. Also, a weird thing, the scanner showed a TPS angle (%) but the volt reading stayed at 0.00 at all times.
I did the mechanical part of the swap but this wiring/computer stuff is over my head. Please help!
Last edited by flattopwill; Apr 10, 2010 at 03:22 AM.
on my f-body it has the extra harnss from speartech (sponcer). I would contact those guys monday to get you the extra sensor and wiring that the 4L60 doesn't have.I took my car to a local tuner in nc. they just raped the tranny tune and then told me it was internal....WRONG!!! After some long thought. I decided to try a different tuner and man what a difference! I cannot tell you how important a GOOD TUNER really is. Even more so for the correct calibration for the tranny. Stick with what you know,pay the right tuner his few hundred and enjoy...thats the best advice I've got for ya, Flattie
Thanks for the advice tmac but I think I already did pay the extra bucks for a good tuner - Nelson Performance. I'm in Ark and they are in San Antonio. On some of the forums people will swear by them. Although, they did mess up once and send me a 4l60e calibration for my 80e. But, they sent me the correct calibration and I confirmed that from watching the commands the PCM gave the transmission on the Tech 2 scanner. I'm thinking this is wiring (internal or external) or a solenoid problem. I hope someone can help.
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So when I left work this morning I had all four gears for about two miles. Then it went back to its old self. WTF??? sticking solenoid maybe? i would think it would stick til it warmed up but its the opposite??
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Send a message and $20 to slow67....get a 4-pole relay, get ready to delete some codes in the ECM,do some MINOR wiring, and ditch the Speartech conversion harness= MUCH BETTER CONTROL of the 4l80e shifting.
Ok next step.....do you know anyone with HPTuners or EFILive? If so, have them hook up the scanner and with the ignition on, but the pcm off, use the scanner to command them on/off and see if you can hear them clicking.
Ok. I do know someone that has HPtuners but can this be done with a locked tune? Can it be done with a Tech 2 scanner? How do I unhook power to the pcm?
Last edited by flattopwill; Apr 12, 2010 at 11:40 PM.
No, leave power hooked up to the PCM. What I mean is, turn the car to the "on" position, but don't start the engine (so you can actually hear the solenoids) and click them on/off.
Ill try that as soon as I can get with my friend with hptuners. Is it possible that shift solenoid A could work for some gears but not for all? Sounds unlikely but I have reverse no problem(which requires functionality of solenoid A) but rarely do I get 1st or 4th. I'd like to check the wiring if someone will tell me what it takes to make 60e harness work on an 80e.
A solenoid is not required for reverse.
If you don't have 1st or 4th, you likely have a failed A solenoid.
If it's intermittent, look at the wiring from the PCM to the main trans connector first.
Hotter trans fluid causes greater resistance in the electrical components, which may cause a problem when the trans gets hot.
I alway replace the shift solenoids with new AC Delco's during a rebuild. Cheap insurance.
If you don't have 1st or 4th, you likely have a failed A solenoid.
If it's intermittent, look at the wiring from the PCM to the main trans connector first.
Hotter trans fluid causes greater resistance in the electrical components, which may cause a problem when the trans gets hot.
I alway replace the shift solenoids with new AC Delco's during a rebuild. Cheap insurance.
A solenoid is not required for reverse.
If you don't have 1st or 4th, you likely have a failed A solenoid.
If it's intermittent, look at the wiring from the PCM to the main trans connector first.
Hotter trans fluid causes greater resistance in the electrical components, which may cause a problem when the trans gets hot.
I alway replace the shift solenoids with new AC Delco's during a rebuild. Cheap insurance.
If you don't have 1st or 4th, you likely have a failed A solenoid.
If it's intermittent, look at the wiring from the PCM to the main trans connector first.
Hotter trans fluid causes greater resistance in the electrical components, which may cause a problem when the trans gets hot.
I alway replace the shift solenoids with new AC Delco's during a rebuild. Cheap insurance.
What exactly do you think is happening when the fluid heats up?
I assure you,
I have a better than average understanding of the hydraulics of the 4L80E.
Reverse doesn't need any solenoid activity to function. The PCM brings the A solenoid on but even without the solenoid, it has reverse.
The solenoid is an electrical device. It has windings internally. Any electrical device will have increased resistance as it gets hotter. Think of a heat soaked starter.
Your solenoid could have a heat related failure due to resistance.
Replace it, it's an $10 part.
Find another transmission shop as well.
I have a better than average understanding of the hydraulics of the 4L80E.
Reverse doesn't need any solenoid activity to function. The PCM brings the A solenoid on but even without the solenoid, it has reverse.
The solenoid is an electrical device. It has windings internally. Any electrical device will have increased resistance as it gets hotter. Think of a heat soaked starter.
Your solenoid could have a heat related failure due to resistance.
Replace it, it's an $10 part.
Find another transmission shop as well.