One problem related to power train driveline has been reported for the 2001 Chevrolet 2500. The most recently reported issues are listed below.
I have a 2001 2500hd chevy 4x4. I noticed a leak on the tail housing on the transfer case at about 30,000 miles. At time vehicle was still under warranty so I brought to dealer and their replaced the seal. I noticed the leak again at around 60,000 miles and replaced seal again and again at 100,000 miles and recently while at a garage I explained the problem to a mechanic and was told that there is a defect with the transfer case and he checked the truck and found the defect. The leak is not caused by the seal failure, the oil pump in the transfer case is wearing a hole through the tail shaft housing from the inside out. I have since gone online to various forums and it seems as though this problems is wide spread and gm is doing nothing about it.