Information on 2nd Design Balancer Hub

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.

Notice: 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.

First and second design balancers hubs are referenced in this bulletin to assist the technician with proper identification of parts. First design balancers that need to be replaced should be replaced with the second design balancer and the appropriate seal.

First Design Balancer Hub

Second Design Balancer Hub

New 2nd design balancers ordered from GMSPO will contain washer 12578073.

Parts are currently from GMSPO.