TrailBlazer 4WD L6-4.2L VIN S (2002)
Harmonic Balancer - Crankshaft Pulley: Technical Service Bulletins
Engine - Balancer Hub Application/Service Precaution
Bulletin No.: 04-06-01-003
Date: March 01, 2004
INFORMATION
Subject:
Information on 2nd Design Balancer Hub
Models:
2004 Buick Rainier
2003-2004 Chevrolet Trailblazer, TrailBlazer EXT
2003-2004 GMC Envoy, Envoy XL
2004 Envoy XUV
2003-2004 Oldsmobile Bravada
with 4.2L Engine (VIN S - RPO LL8)
Depending on the vehicle and assembly plant, during the late 2003 model year or early 2004 model year, the design of the engine balancer hub was
changed. Care should be exercised when servicing any of the vehicles listed above.
The 1st design hub is straight and smooth. The 2nd design balancer hub has a step machined on it. The inside diameter of the seal has changed, but the
outside diameter has not. It is possible to install either seal into the front cover, however, the incorrect seal will leak between the seal lip and hub of the
damper.
Note:
Be sure to service with the proper combination of balancer, seal and washer. Mixing combinations could lead to an excessive engine oil leak and
possible engine failure.
