I need some help to diagnose a noise coming from my transfer case (BW 1356). The noise sounds like a "bearing noise" or "grinding noise" coming from the rear of the case. The noise only occurs when in 4 wheel drive. If the front drive shaft is removed(and in 4 wheel drive) there is no noise. I just had the transfer case overhauled 3 weeks ago, the noise was there prior to the overhaul. My Bronco is at the shop today. They pulled the case and couldnt find any obvious problems. Is there something that might be easily over looked ? The owner of the shop ( a friend) said that he heard that the main shaft in those cases somtimes bends. He was going to send it to his machinist to make sure its not bent. Any and all suggestions would be greatly appreciated.