For 1990-2009 cars

# DISTRIBUTOR GEAR WEAR ALSO REPLACE CAM GEAR

#### MODELS AFFECTED: ALL HT4100 ENGINES

Previous bulletins on this subject, such as T-86-79, have described detailed procedures for diagnosis and repair. Most important among these procedures is the requirement that when distributor driven gear wear is discovered, the distributor drive gear (camshaft) must also be replaced. The reason for this is that the two gears wear together in a pattern and when only one of the pair is replaced the likelihood of a repeat faiture is very high.

In spite of this requirement, Cadillac continues to receive warranty claims indicating that only the distributor driven gear was replaced. The claim history frequently indicates a later repeat failure. In the interest of customer satisfaction, labor operation J4520-B (Distributor Driven Gear Replacement) has been cancelled. Operation T6135 described in Bulletin T-86-79 must be used for this repair.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.