GM Service Manual Online
For 1990-2009 cars only

Balancing Information

Torque is transmitted from the transmission to the axle through the propeller shafts and universal joint assemblies. The number of propeller shafts and universal joint assemblies vary with the vehicle wheel base. All propeller shafts are the balanced tubular type.

There are two different methods for achieving balance within the propeller shaft system during the manufacturing process. Vehicles that have one or two propeller shafts have those shafts balanced individually. Vehicles that have three propeller shafts utilize a system balance. System balance is accomplished by effectively balancing the front, center, and rear propeller shafts together on a special balancing machine. When manufactured, the three-piece propeller shaft system and the transmission mounted parking brake assembly are aligned with arrows painted on the shafts. In order to ensure that these parts are assembled in proper relation to each other, mark all components before disassembly. Minimizing driveline imbalance in a three-piece propeller shaft system is critical for maintaining the lowest vibrational noise possible. When servicing a three-piece propeller shaft system, take special care that proper balance is maintained. In the event that a single propeller shaft within a three-piece propeller shaft system required replacement, follow one of the following procedures in order to properly balance the three-piece propeller shaft system:

    • Consider replacement of all three propeller shafts in the system by ordering the three-piece propeller shaft assembly
    • Replace a damaged or worn propeller shaft (prebalanced as received) and rebalance the remaining shafts individually or as a system
    • Replace a damaged or worn propeller shaft (prebalanced as received) and evaluate the resulting driveline. If necessary, correct remaining propeller shaft imbalance by using procedures in Vibration Diagnosis in General Information.