UPDATE- HM4L60/700-R4 A/T DIAGNOSIS

Model and Year: 1990 PASSENGER CARS WITH 4L60 TRANSMISSION 1990 LIGHT DUTY TRUCKS WITH 4L60 TRANSMISSION

This bulletin provides a revised Preliminary Check Procedure and Shift Speed Chart for 1990 HM4L60/700-R4 transmissions. These charts have been updated since publication of the 1990 Service Manuals. Please make reference to these changes in your service manuals.

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.