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.