Center Bearing
WARNING: This page does not describe the selected car, but rather 12 other vehicles, including the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, 2002 Chevrolet Cab & Chassis Silverado, and 2001 GMC Sierra. However, it is still accessible from the selected car via links, so may be relevant.
Center bearings support the driveline when using 2 or more propeller shafts. The center bearing is a ball bearing mounted in a rubber cushion that attaches to a frame crossmember. The manufacturer pre-lubricates and seals the bearing. The cushion allows vertical motion at the driveline and helps isolate the vehicle from vibration.