4L80E TCC PWM in 1st

[Murphy's Law]

I'm having issues with the PCM commanding TCC lockup in 1st and 2nd although I believe the tune has this disabled. I would love for anyone to review and provide feedback.

Some quick history: Vehicle is my 1985 C10 short bed. 5.3L LM7 is from a 2005 GMC Sierra. PCM is from the '05 and was originally programmed for it's 4L60e. I paid a local dyno shop to remove the VATS, segment swap to the 4L80e, and update the tune for the new rear gear and tire size. The truck would run, but I still had DTC's from the 4L60e and the truck was undrivable. It would shift into 2nd within 5-8 mph and stall at stops as if the TCC was still engaged. Local shop was unsupportive. Long story short, the tire size and DTC's were wrong. I updated the tune with the tire wizard and then used Bluecat's excellent transmission software to get the shift tables close. I also removed the 4L60e DTCs


Current issue: I'm showing TCC PWM in first gear, and naturally shifting into second with it still locked. I'm almost positive this is disabled in the tune, so am I looking at a failed segment swap? I also tried to log TCC Slip via user math (engine RPM minus Trans ISS) but I'm not confident in that data yet. Histogram showed a random spike, negative values, exc. Any guidance would be greatly appreciated!

Rich

1985 C10 Trans Troubleshooting.hpl1985 C10 Trans Tune Rev3.hpt

[Murphy's Law]

OS is 12606961. I hope I'm wrong but by my research... segment swapping to a 4L80e is not possible. I've submitted a help ticket through HP Tuners and will update. If this is true, I'm hoping I can change the OS without burning though another 2 credits. Any guidance from the forum members is greatly appreciated!

Thanks,
Rich

[ScarabEpic22]

Looks like your current OS is newer than the 80E segment ones in the repo. You'd have to pay 2 credits to flash the older 12592618 OS in and you could segment swap that, or start with a base 80E tune.

Does anyone have OS 12606961 with a 80E segment (if it exists)? I checked a handful of files, and they're all 12592618.

How is your trans wired to the PCM? Is it using a relay harness, pins swapped, vendor kit?

Honestly it sucks, but if you can't get segment swap your 12606961 OS, I'd pay the 2 credits to license a 12592618 file and be done with it. Your current file does not look like it's been segment swapped, changing the "Trans Type" field does nothing tangible. It's basically a nice indicator.

[Murphy's Law]

Thanks for the info! The trans is wired as a factory 5.3L 4L80e install, no relays, vendor kits, etc. I repined the trans harness. Everything is terminated at the PCM per '03-'07 DBW Auto, and added another twisted pair for the ISS. I've ohm'ed out every wire individually pin to pin and pin to ground, checked all solenoid resistances, and verified no issues with connectors. Everything is correct.

I received a response this morning from support and it's confirmed, OS 12606961 was never released from the factory with a 4L80e tune and therefore no segment swap is possible. Looks like I'll be licensing a 12592618 tune. On the plus side, if I pick another 99-07 Sierra tune would it count towards the unlimited license? Any advice on verifying my current PCM hardware can run the new OS file i.e. is there a resource cross referencing OS vs PCM? Thanks again!

[ScarabEpic22]

Good to know the circuits are correct, downside is the solenoids are wired properly but not being controlled by the PCM properly with a 60E segment. 60E vs 80E uses the same circuit/pin for different things. I'd have to look at the diagrams again, but I'm pretty sure the 60E 2-3 shift solenoid circuit is used by the 80E as the TCC solenoid circuit....

I would pick an 05 Silverado/Sierra 12592618 OS and just have it be as close to the existing one you're using. It would count towards the year/make (6cr total) if you used a Sierra one from a 6L truck. Up to you if you'd rather license a LQ4 6L + 80E combo and change the engine side to match the 5.3, or license a 5.3+60E and seg swap the trans +trans diagnostic segments.

[Murphy's Law]

Ok, got a file made up. Base file was 2005 Sierra 5.3L. Then compared to 6.0, segment swapped to 4L80E. Only question I have is do I need to change the VIN in this file to match the current tune?

[Murphy's Law]

Everything looks good! I licensed the new OS and wrote entire. I copied the old trans tables over to ensure the only change between tunes was the OS. Logged a couple of runs around town and the PCM commands for TCC are exactly in line with the tune. New OS appears to be the correct solution. Thanks again

[ScarabEpic22]

Glad you're up and running! Thanks for posting back in this (and the other) thread so others are aware in the future. Seems like 05 OS 12606961 is one to avoid for swappability!