Nah they do the sheriffs and police dept tahoes. They know the 6L80. And the warranty is covering the 2 times I've been back in there. Not paying someone new when I have a warranty. Slipping would indicate pressure to me, no? And it was PERFECT since they had it last and 20-25 miles later, here we go again. That many bad TCs in a row? I know they'll fix but I want to know how these could be getting damaged.
Find out what or who's torque converters your builder is using and perhaps recommend they make a change if buying from one large TC reman company or another...
If the TC is a factory-level replacement, that by itself would explain what's happening and why as the JMBX converters are notorious for failing early and often. Other things can be excessive wear in the pressure regulator valve in the lower valve body, TCC limit valve, TCC apply valve, weak TCC solenoid in the TEHCM, etc...
Yea, I'm sure they'll fix it (again) but if you were bringing the transmission to me for the first time, I'd do the following:
- Fully bench test the TEHCM for electrical and mechanical function
- Fully disassemble, clean and reassemble then vacuum test both valve body assemblies (upper and lower)
- Fully disassemble, clean and reassemble then vacuum test the stator support valve trains, including the pressure regulator/boost circuits, TCC apply and TCC limit
- Visually/physically inspect the pump, VB mating surfaces, spacer plate, check ball condition, etc
- Cut the torque converter open and see how thick the converter clutch is
Once I was done and still didn't have a positively identified smoking gun, I'd start looking at other parts/systems on your vehicle like your flex plate, engine, driveline, suspension, rear transmission mount, etc....