Hey, I'm new to this forum, so sorry if I do something stupid. Anyways, I'm having some 4wd issues. Couple months ago, I had the transmission rebuilt, and since then, my service 4wd light was on, and my dash switch wouldn't light up, or respond or anything, well, after replacing the encoder motor on the transfer case, the dash switch, the TCCM, and the actuator on the front axle, the service 4wd light is gone, and the buttons work. The only problem is now, when I first picked it back up from the dealer, i noticed it was in 4wd, so I pushed the button to put it in 2. Well, when i went to go, it didn't move, it acted like the transfer case was stuck in neutral, so I pushed the 4hi button again, and it made a loud bang, then acted like it had locked in, then i pushed the 2hi button again, and then it was fine. I tried using 4wd again tonight, and that same thing happened, but this time when i had the shifter in neutral and tried to change it to 4wd, i could hear the motor on the transfer case working, and i know the actuator on the front axle works, but it wouldn't engage into 4wd. Then i put it in park, and it made a sorta grinding noise, like something was rubbing against a gear in the transmission. I also tried 4 low, and even though it felt like it changed the gear ratio (more torque) the front tires were still not engaged. It also did the whole thing where it felt like it was in neutral, in fact, i put it in park one time, and it just kept rolling, so I dunno. I need some suggestions! I'm baffled now. Oh, btw, it's a 99 silverado z71 extended cab w/ the 5.3. Let me know your thoughts!