Yama Sutra

2011 gmc Sierra 1500 6.2l I have been trying to figure out what is going on with this "service 4wd" message. Started after a 4 hour highway drive. Got to where I was going and parked it which is when I got the first message. When I went to start my truck 2 days later my selector knob says it was in 4wd low but I left it in 2wd when I parked. I tried shifting from park to reverse and drive but neither would move the truck. I pulled the fuse while in neutral with the engine running and stuck it back in and it shifted to 2wd. Left it like that until I drove 4 hours back home. Now that I've been home I've replaced transfer case control module (encoder motor) and 4wd actuator. Tried cleaning the ground wire under drivers door. Tried the process for relearning the clutch (turn off for 30 seconds, turn key to accessory then shift to neutral, twist selector knob past 4wd low for 30+seconds). Nothing has worked yet. Trying to unhook ground from the battery for a half hour right now. Don't know if this has anything to do with this problem but I had power steering issues which dumped power steering fluid everywhere while running and the moving parts slung that ps fluid everywhere. Did I fry something?