IMPROVED PERFORMANCE/LAUNCH AXLE RATIO INFORMATION

MODELS: 1983 S/T-15 PICKUPS AND JIMMYS WITH RPO LR2 AND RPO YF5 (2.8L V6 ENGINE AND CALIFORNIA EMISSION)

To improve performance and launch on the subject trucks, the following combinations of transmission and axle ratio are now certified and may be substituted under warranty as a field fix upon customer complaint.

S-15 pickups with manual 4 and 5-speed transmission - maximum ratio is 3.73 regardless of tire size.

T-15 pickups with manual 4 and 5-speed transmission maximum ratio is 3.73 with P235/75 R15 tires.

T-15 Jimmys with RPO MXO automatic with overdrive - maximum ratio is 4.11 with P235/75 R15 tires.

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.