I'm working on a 6L80 that's in a 2018 Silverado 4.3L with 125k miles, mostly highway. Friends vehicle. The trans has a rough shift after it warms up. It's also got a shudder. Code is P0777. Looking online suggests replacing the solenoid pressure switch films so I dropped the pan and removed the valve body to access the TEHCM. There is no metal in the pan so I'm thinking the torque converter is ok. Removal of the TEHCM showed the orange switch diaphrams are ok after I removed them. The solenoids all have consistent measurements of .8 ohms closed and 12k ohms open. At this point I'm scratching my head on what else to look at?