For 1990-2009 cars

# GEAR CLASH/HIGH EFFORT COLD (FLUID RECOMMENDATIONS)

#### MODELS AFFECTED: 1983-88 SKYHAWKS WITH ISUZU 5-SPEED MANUAL TRANSMISSIONS 1985-87 SOMERSETS WITH ISUZU 5-SPEED MANUAL TRANSMISSIONS 1986-87 SKYLARKS WITH ISUZU 5-SPEED MANUAL TRANSMISSIONS

Some owners of the above vehicles may comment of gear clash and/or high shift effort during cold weather operation. If this condition is reported, drain the transmission and refill it with STF (Synchromesh Transmission Fluid).

After draining and repairing any 1983-1987 Isuzu 5-speed manual transmission, it is strongly recommended that only STF be used to refill the unit. Refilling the unit with 5W-30 manual transmission fluid, Part Number 1052931, is acceptable; however, it will not provide the lower shift efforts that the newer STF provides. The most notable reduction in shift effort will be during cold weather operation.

Mixing STF with 5W-30 manual transaxle fluid is also acceptable, however, as the volume of 5W30 increases so does the shift effort.

#### NOTICE: DO NOT USE ANY AMOUNT OF ATF (AUTOMATIC TRANSMISSION FLUID) IN ANY MODEL YEAR. THE USE OF ATF MAY CAUSE GEAR CLASH AND RESULT IN SYNCHRONIZER DAMAGE.

#### Service Parts

STF Part Number 12345349 5W-30 Manual Transmission Fluid Part Number 1052931

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.