GM-51336 is a double-ended tool (3 functions) used to install the front output shaft's front ball bearing into the transfer case's front housing, install a needle-type bearing into the drive sprocket, and install the front output shaft's rear bearing into the rear housing. The front output shaft's front ball bearing is installed until it bottoms out in the case half bore. The drive sprocket needle bearing must be installed to a specific depth in the sprocket. The front output shaft rear needle bearing is installed to a specific depth. Current GM tools will not fit either bearing, and the drive sprocket bearing position is critical to the operation of the drive chain and sprocket.