I have a 2001 Chevy Silverado and I have replaced the transmission and transfer case and I still have popping in the transfer case, what could it be? The popping only occurs when in 4 wheel drive and turning to the right.

 

Have you taken it to a mechanic? That's probably the best and most practical option. Unless you got technical know-how in this type of thing. Otherwise, you might harm your vehicle.