Gen3Convoy

I am tuning with hp tuners and I have asked tis same question. My converter is disengaging lock-up when there is no load, and will re-engage when I start to accelerate. The transmission is fine. it is something in the tune that I can't quite figure out. Does anyone have a suggestion? TIA

Full Power

In for answers here.
Having rather violent TCC LOCK/Unlock problems as well. Took all the ""misfire Tables" to max value.
Workaround at present is to disable Lock-up in Tow-Haul mode, and anything over 70 MPH I have to run UN-Locked in Tow/Haul.
Can manually LOCK converter in Diagnostics, and it WILL stay locked.
Something mysterious in my P59 2 Bar SD tune is THRASHING my TCC solenoid at highway speed.

Gen3Convoy

Y issue starts at 45 mph and up. My converter will lock and stays locked until I hit a flat area or I let off of the gas. If I am coasting down a hill and the truck continues to increase in speed it stays locked. If I am going up a hill it stays locked, but If there is any discrepancy between the TPS and the speed of the vehicle it will disengage and acts like it is floating between 3rd and 4th gear until I accelerate. Then it re-engages and starts pulling again.

Full Power

There seems to be a LARGE number of condition(s) and aparameters that can or WILL cause the PCM to Un-lock the 4L80 TCC.
I will begin a list, and hopeful that some experts will ADD to the list, or make corrections to my attempt.

P59 TCC Unlock Parameters:

1) Brake pedal switch 12 volts= "Can Lock".... 0 Volts WILL UN-Lock
2) Trans Temp sensor Open Circuit default to -40 Degree temperature WILL UN-Lock
3) ISS speed not equal to Crankshaft speed ( apparent converter slip) WILL UN-Lock
4) TPS 0% ( coasting) WILL UN-Lock
5) 1st gear cannot Lock
6) 2nd thru 4th Gear CAN Lock above TCC speed vs gear table, but subject to Min-Max TPS settings.
7) Misfire detected TCC WILL UN-Lock