A new, hardened washer, p/n 23504011, is available for improved clamp load of the crankshaft sprocket to the crankshaft by the crankshaft bolt. Installation torques for the hardened washer have been increased to 177 to 185 ft.lbs. (240 Nm /250 Nm).

Parts are currently available from GM and other suppliers should damper loosening occur, resulting in the crankshaft sprocket shearing the lead alignment key, repairs should be made using the new washer and torque value. Examine the crankshaft sprocket, and assure before reassembly that there is no damage to the keyway. During the assembly of the crankshaft sprocket to the crankshaft, GM Goodwrench Thread Locker 272, p/n 12345492 or equivalent should be applied to the crankshaft post for 360 degrees at the rear’ crankshaft key area only. Thread Locker 272 material should not be applied to the sprocket inside diameter (see Figure 1).

Some or all of the technical information was provided by the Automotive Parts Remanufacturers Association (APRA). For more information on technical bulletins available through APRA call 703-968-2772 or visit www.AutoBulletins.com.