4L80e TCC Issues / Tuning.
 

My combo is a 04 6.0L 99 4L80e 90 NP241c with 32 spline input.
TCC has never worked since day one when i drove her home from vegas where a received a special bend over 16k LS swap that i had to completely redo when i got home.
This week i pulled the trans pulled the pump..dropped in new pump gears...bushing and seal. Did the drill out of the drain hole and the HD2 mod inside the pump. Flipped her over and did the rest of the HD2 shift kit with a brandy new GM valve body. Installed a fresh Phx Trans converter and put her back together and hit the highway. Still no TCC. Went thru the brake pedal to the ecm...C1 pin 33..watched test light vrs brake pedal. Good to go. Went down to trans and ohmed all the solenoids...good. Function checked them with a 9v battery....good. I swear my gut tells me its in the ecm parameters from years of cat/cummins/detroit/rockwell etc. work. So....to change anything thats not set right i will need EFI Live and or HP tuners and a sharp tuner to get this mess fixed. Harness is from PSI...they flashed the new ecm and sent it to me.

What do my square brothers think about this? Who to trust with tuning and where / who do i start with?

DW

Re: 4L80e TCC Issues / Tuning.
 

Couple possibilities. If your getting false knock at all from a cam swap, the TCC will stay unlocked thinking there is an issue. If thats not the case, then your trans tuning needs to be adjusted. Its possible that your lock and unlock are set at conflicting interval.

Luckily that part isn't the hardest thing for a tuner to mess with. Barring some unusual mechanical problem that is. I don't know WHY they would have messed with the lockup settings drastically (usually its way more common to get "tunes" with the trans tables completely untouched).

Re: 4L80e TCC Issues / Tuning.
 

Since i have gone thru the TCC circuit with a fine tooth comb and i was still scratching my head...i took it to a trans shop this am. He had an older snap on brick scanner and of course it didn't want to play well with my ob2 port due to it being a split circuit to run the dakota digital can bus box....
So we just took it for a drive and i got schooled. Lol. Nothing wrong with the TCC circuit. Working as designed. I guess being my first 4L80e and being used to a 700R4 the way the TCC comes in is way different. I was expecting something more pronounced.

Now that i have the monkey off my back its tune time once i can figure out who to go with. She's bone stock. Single exhaust and all. Save the 4.88's and 35's at 5k of elevation.

DW

Re: 4L80e TCC Issues / Tuning.
 

Yeah, the 4L80E TCC comes in more gradually...the PWM ramps it in, so you don't feel it like another gear shift.