Truck is 5.7L ,CK1500 4wd Silverado with automatic transmission. Used 4wd in snow and slush and now in 2wd in reverse it will back up but it's like it's pushing very hard. Have to really give it lots of throttle to get it to move in reverse. It doesn't seem to be slipping, just lots of resistance. In drive, forward, it seems OK. All 4wd lights are out when in 2wd. When this started it did seem to shift up a bit hard , but it shifts up OK now. I get these PCM codes. Haynes says-
66- 3-2 shift control solenoid----------code 66 will set if the pcm detects an open or short circuit in the 3-2 solenoid 67- torque converter clutch solenoid---code 67 will set if the pcm detects an open or short circuit in the torque converter clutch solenoid circuit 81- 2-3 shift solenoid------------------code 81 will set if the pcm detects an open or short circuit in the 2-3 shift solenoid circuit 82- 1-2 shift solenoid------------------code 82 will set if the pcm detects an open or short circuit in the 1-2 shift solenoid circuit 83- Torque converter clutch-----------Code 83 will set if the pcm detects an open or short circuit in the TCC solenoid circuitAny suggestions before I take it to a Transmission shop would be greatly appreciated. Thanks