GM Service Manual Online
For 1990-2009 cars only

INSTRUMENT CLUSTER GAGE REPLACEMENT

VEHICLES AFFECTED: 1988 C/K MODELS

If the vehicle tire size or axle ratio is changed, the speedometer must be recalibrated for accuracy. Use speedometer calibration service kit Part Number 25085515, which consists of a connector, two clips and usage instructions. The connector can be used ten times. Clips are available in packages of 20, Part Number 25085993.

Complete speedometer calibration instructions are in Section 5A3-22 of the 1988 C/K Service Manual.

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.