POWERTRAIN VENTILATION KITS MODIFICATIONS

VEHICLES AFFECTED: 1988-89 C/K SERIES (TRUCKS)

Some 1988-89 C/K trucks used in severe duty/off road operations may experience premature wear of powertrain components due to dirt and water entry through the vents.

Modifications to the vents for the front axle, rear axle, transmission and transfer case can reduce the amounts of dirt and water entering the assemblies and decrease the chances of premature wear in severe duty/off road operations.

Prior to modifying the rear axle vent, remove axle cover and inspect for contamination. If water or dirt are present, flush out axle housing, ring and pinion with a suitable solvent such as choke cleaner (GM Part Number 12345109 or equivalent). Reinstall housing cover and gasket and refill the housing with the lubricant specified in the Light Duty Truck Service Manual or Maintenance Schedule. If the axle lubricant does not show signs of contamination, reinstall housing cover and gasket, and refill the housing with the lubricant specified in the Light Duty Truck Service Manual or Maintenance Schedule.

The following powertrain ventilation kits are available, which contain the components necessary to perform the modifications:

P/N 10951640 - Powertrain Ventilation Kit - C Models P/N 10951641 - Powertrain Ventilation Kit - K Models

Due to the various powertrain combinations available, 5/16" vent hose P/N 9438315 (24 ft. roll), should be ordered as required.

The appropriate rear axle vent shield should also be ordered separately:

P/N 728358 - 8 1/2" Ring Gear Axle

P/N 728434 - 9 1/2" Ring Gear Axle

A rear license lamp guard kit, P/N 10951642 may also be installed as part of the modification.

A set of instruction sheets is included with each kit, which details installation of the components.

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.