Everyone’s fav topic: 6l80 issues before and after teardown

[Starkworks]

2020 Chevy Suburban w/ 110,000 miles

 

Before tear down issues: progressive slipping/flares from drive. Noticed predominantly after driving for a period of time and warmed up. Able to engage and drive after a period of cool down. A code finally popped up with a p2723. Lost all gears, including reverse. I had to have the truck towed home.

 

During tear down:

- metallic dust in the pan. Assuming torque converter failure, I proceeded with a complete tear down.

- Pulled apart the valve body. No check balls in appeared to be shrunken or stuck. The valves appeared to be free moving and no excessive wear on any of them.

- TEHCM: all TFP switches were intact.

- Disassembled Stator Pump: slight scarring on the pump body side and pump cover surface.

- 1-2-3-4/3-5-R housing, friction and steels looked good. Pistons good. Bearing no abnormal wear. O rings intact. No apparent cracks in weld.

- 4-5-6 housing, friction and steels were burned up. Piston looked intact. No cracks in housing though.

- center support and components looked good.

- 1-2-3-4 clutch hub looked good

- 2-6/3-5-R clutch hub looked good

- Rear carrier was intact and all gears were freely spinning.

- output carrier was fine.

 

Assembly:

- valve body: cleaned and installed transgo kit with new check balls. Vacuum checked all valves.

- TEHCM: cleaned and changed orange pressure switch covers and seals. All continuity testing was good.

- Stator pump: buffed out the slight scarring. Installed transgo valve kit. New seals. Reused other components. Installed new gasket.

- kept all bearings throughout as they didn’t have any scarring and thrust bearings moved easily. Nothing appeared out of place.

- replaced all frictions and reused metals in all but the 4-5-6. Replaced 4-5-6 metals and frictions.

- 4-5-6: new pistons, frictions and steels. New Teflon. Pressure checked on stator.

- 1-2-3-4/3-5-R: new frictions and pistons. New O rings. I did not specifically test for leaks as I heard that the welds are improved in the newer 6L80s. But, I did place on stator and test. No leaks that I could tell. Stator kept pressure as well.

- 2-6: new frictions

- low and reverse: new frictions

- center support: pressure test was good

- lubed everything up 

 

After assembly:

- refilled with dexron VI

- started the truck up and have reverse. Drive works, but doesn’t shift. Flares at about 5 mph

- checked manual mode:

- 1st flares around 5

- 2nd feels like it’s binding? When in second truck doesn’t move at all and feels stuck.

- 3-6 flare around 5.

- hooked an autel scanner up and solenoids and switches appear to be working in the mode they are supposed to.

- went ahead and ordered a TEHCM, but will wait to install until I can rule of everything else.

 

No clue what to try from here. I am an amateur at this but love learning about these transmissions! Watched quite a many hours of NickTransmission.