PLASTIC SPEED SENSORS AND NEW TOOL TO REMOVE AND INSTALL

Model and Year: 1990 LIGHT DUTY TRUCKS WITH 4L60 (700-R4) AUTOMATIC TRANSMISSION

This bulletin covers usage of an all plastic internal transmission speed sensor which has been increased to include twenty-three models of the HYDRA-MATIC 4L60 transmission. All 1990 General Motors light duty trucks and vans will use the Rear-Wheel Anti-Lock Brake System which requires the use of the internal transmission speed sensor.

Beginning Start Of Production 1990, some of the following models of the HYDRA-MATIC 4L60 were built with the plastic internal transmission speed sensor: (See Figure 1.)

OCAM, OCBM, OCCM, OCFM, OCHM, OCJM, OCKM, OCLM, OLAM, OLBM, OLCM, OLDM, OMBM, OMJM, OMSM, ORAM, ORBM, OSAM, OSHM, OWAM, OWBM, OWCM, OWDM

The remaining models are scheduled to receive the plastic internal transmission speed sensor during the 1990 model year.

A new available tool has been developed for the plastic internal transmission speed sensor. This tool is necessary to prevent damage to the speed sensor during its removal. The tool is available through Kent-Moore as J-38417 - Speed Sensor Remover and Installer.

Part Number Description ----------- ----------- 8673299 Speed Sensor - Internal Transmission

Parts are currently available from GMSPO.

Information on speed sensor removal and installation is included in the Unit Repair Section of the 1990 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.