ericgerber79

the thread I tried posting has not appeared on the forum yet.

I believe I posted it In the correct forum

Gm> Tuning, diagnostics ect..

having a tuning gremlin with my 4l80e swap 2002 gmc sierra 1500. I posted all relevant info and really took a lot of time to go in depth on what I had done, tried, and specifics and uploaded my tune as an attachment, I would hate to have to type it all up again... hopefully it wasn't lost and is just awaiting an admin approval

ericgerber79

Well this thread came up somehow so I guess Ill type it all up again.


2002 Gmc Sierra 1500 2 Wheel Drive
5.3 LS with Howards Cam 281/284 578"/587" 115*
Pac 1218s
RaceMMI Twin Turbo Setup
ARP Headbolts
ON3 Dual 320lph Fuel Pumps running E85
FID1000 Injectors

4L80e transmission just fully rebuilt with new internal harness and all sensors, & im using Nelson Performance Swap Harness
Circle D Specialites Torque Converter Pro Series Stage 3 Multi Disk


Speed Density Tune with HPTuners Standard
GM OS: 1252013
2 BAR OS
GMC Cyclone IAT Sensor
AEM Wideband


I think there is some gremlin in my tune somewhere that Is causing my issue


Transmission goes into limp mode where when I start it up it goes into reverse nice I pull out of driveway, go around block in the D position on the shifter it shifts up into second and then even when I come to a stop it never downshifts. it will stay in either 2nd or 3rd no matter where I try and manually shift it to with the shifter until I pull up the codes on the scanner that pop up. It will still go in reverse and park just fine but if I shift to D or 1-2-3 it will just stay in either 2nd or 3rd
a couple Maf Codes & an evap code
and the ones I think that are relevant P0740 ( TCC solenoid circuit Open & P0785 Shift/Timing Solenoid)


If I put it in park and clear the codes it will go into first gear if I put it in D but the same codes will almost instantly pull back up and if I were to drive it again and shift out of first it would limp and stay in whatever gear I got up to either 2nd or 3rd.


Now I had a really hard time trying to find a 1252013 OS like I have, I believe I did find one on one forum and I segment swapped the 4l80e Trans and Trans Diag portions of that tune into my base tune before ever even trying to move the truck.


Im just an at home guy trying my best to learn what I can and do the basics myself. Any help or insight into what I should look into next would be appreciated.


Im not sure if it is a gremlin in the tune that I am missing or if maybe there is something electrical going on in the truck wiring


I ran the 2 wire front vss to the correct pins on the PCM and re used my 2 plug NSS because the 4l80e NSS had one elongated plug that didn't work for my wiring harness. I don't think that would be the issue?


Now I can say that when I bought the truck and it was still stock and had a 4L60e in it had a weird trans problem where it would shift through 1-2 fine but then rev way up in third and act like it was slipping and a TCC Solenoid code would pop up. I figured it was just a trans issue and knew I was swapping a 4l80e in but if anyone has any pointers on what I should check wiring wise on the harness side of things




Also when I was googling the issue some people were saying turn off codes P0740 & P0785 and also another one P1860 and or possibly 1870/80??


I tried disabling the P0740 P0785 & P1860 to No Error Reported and re flashed the truck and all that did wsa make the torque converter stay locked up in 1-2-3 but I could manually force the gears to change by shifting on the column. but it would obviously try and stall out coming to a stop so that is no good and not the correct fix.

ericgerber79

attached is tune, It may still have the 3 codes turned off in this copy but I Have since changed them back to MIL on second error

ericgerber79

attached

Atomic

iTrader: (42)

Why do you have your shift pressures set so high? You are commanding full pressure all the way down to about half power.

Can you post up a log file as well? Logging TCC slip, trans current gear, trans temp, and force motor current would help.

Did you change the wiring at the trans connector/pcm? A couple wires need to be moved and you didnt mention this in your post.

ericgerber79

I honestly don't know anything about what to set shift pressures at or anything trans related, I only found what I believe was the same OS with a 4L80e and did the segment swap for Trans and Tran Diag Segments. So the person I got that segment from must have adjusted those like that.


do you happen to have a file you could share that I could copy the shift pressure tables from to change that?


I will absolutely get a log file tonight with those things you asked for included on it and post it up here.


I thought I did mention about the wiring in my post but I may be mistaken.


I bought the Nelson performance wiring conversion harness which adapts the 4l60e main plug to the 4l80e plug without having to move any pins.


and the second part of that harness comes with the plug and two wires for the front vss sensor that comes on the 4l80e that I ran up to the PCM and plugged into the pins 22 and 23 in the correct spots.

Atomic

iTrader: (42)

What all is done of the transmission? Find just a stock 4l80e file and use the stock transmission settings, using the show differences window makes this really easy, just copy over all differences. Doesnt necessarily have to be the same OS, just same year ish.

Changing the plug is literally 3 or 4 wires, but if you can manually shift it and command it with the scanner it probably isnt that. Also log Input Shaft Speed with the scanner to make sure your ISS is hooked up correctly.

ericgerber79

Thank you so much for the help, since your saying it doesn't need to be the exact OS and just close in year or such I will hop on the HP tuners website and pull a stock file with a 4l80e and use the show differences option to copy over only those differences tonight.


and then I will flash that in and make sure I have all the things you asked for logging and take a drive around my block.


Thanks again.


Transmission was fully rebuilt by a friends shop, completely torn down, all electronics replaced and a few upgrades done to hold up to the power level I was looking for, but it wasn't anything too special. I don't have my receipt on me to go through exactly what all was done.

ericgerber79

Once the codes set which is pretty much almost immediately the truck will not respond to me manually shifting it. It will stay in the gear it was in

Atomic

iTrader: (42)

Yea, you just need the 80e settings, you dont need to do the segment swap again since its already for an 80e.

Limp mode is it will stay in 2nd gear. If you can command a gear and it actually goes to the correct gear then the trans itself and wiring is probably ok so the problem is in the tuning which is why I say start from a stock file.