Engine - Sprocket Key Shear On Crankshaft
89chevy34GMC NUMBER: 89-6A-116
GROUP: 6A - Engine Mechanlcal
DATE: November, 1989
CORPORATE
NUMBER: 836312
SUBJECT: CRANKSHAFT SPROCKET KEY SHEAR
MODELS: 1982-89 C/K, R/V, P TRUCKS, AND G VANS EQUIPPED WITH 6.2L DIESEL (VIN CODE C, J)
THIS BULLETIN CANCELS AND SUPERSEDES BULLETIN 89-T-26 TO CORRECT A TORQUE SPECIFICATION. ALL COPIES OF 89-T-26 SHOULD BE DISCARDED.
Figure 1:
A new hardened washer, P/N 23504011 has been released for improved clamp load of the crankshaft sprocket to the crankshaft via the crankshaft bolt. Installation torques for tbe hardened washer have been increased from 190 N-m (140 lbs.ft.) to 240 - 250 N-m (180-185 lbs.ft.). Should damper loosening occur, resulting in the crankshaft sprocket shearing the lead alignment key, they should be repaired using tbe 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 cranksbaft, GM Goodwrench(R) Thread Locker 272, P/N 12345492 or equivalent should be applied to the cranksbaft post for 360 degrees at the rear crankshaft key area only. Thread Locker 272 material should not be applied to tbe sprocket inside diameter (See illustration). Parts are currently available from GMSPO. Use applicable Labor Operation and Time.