I have a 99 gmc sierra that I just bought. While im driving down the road I noticed a whine in the drivetrain, I noticed that the 4wd switch wasnt lighting up so I checked the fuses and the ATC fuse had been removed. I put in the correct fuse and the 4wd switch came on. Once it came on it said the truck was in 4hi. I tried to switch it into 2hi and theres a whining noise coming from the transfer case. It makes 2 long whining noises and the 2hi light flashes the it goes right back to 4hi. I cant get it to change into any other mode (4lo, auto4, 2hi). I bought the truck a week ago and im scared im going to grenade the transfer case by driving it like this. Can you please point me in the right direction.