DELAYED REV. TO DRIVE IN COLD OPERATING CONDITIONS

Models Affected: 1989 6000, SUNBIRD, GRAND AM, FIERO AND LEMANS

BULLETIN COVERS: (Figure 1) --------------- New cross drilled holes (larger in diameter) drilled through the Manual Valve and a second Cold Window that has been added to the Thermal Element. These changes increase the rate of fluid exhausted through the Manual Valve during cold operating conditions, which reduces the potential for delayed engagement when shifting from Reverse to Drive.

DATE OF PRODUCTION CHANGE:

June 12, 1989, (Julian Date 163), the new Manual Valve and Thermal Orifice Assembly went into production.

SERVICE PROCEDURE:

The new Manual Valve and Thermal Element assembly can be used on all past models. If replacement of the Manual Valve is necessary, the new Manual Valve (cross drilled) and Thermal Orifice must be used together.

SERVICE PARTS INFORMATION:

When ordering a new Manual Valve and Thermal Orifice, refer to the following number:

Part Number Description ----------- ----------- 8666494 Assembly, Manual Valve with Thermal Orifice

Parts are currently available from GMSPO.

SERVICE MANUAL REFERENCE:

Whenever servicing a THM 125C/HYDRA-MATIC 3T40 for this condition, refer to the procedure given in the 125C/HYDRA-MATIC 3T40 Unit Repair Section of your Service Manual.

SERVICE NOTES:

The retainer clip for the temperature orifice must be 11.2mm +/- 0.2mm (0.44" +/- .008") inside the link end of the Manual Valve for proper operation. If the Thermal Element has moved forward due to a retaining clip that has fallen out, the vehicle may exhibit a loss of Drive and/or Reverse. A clip that has fallen out may be located in the bottom pan.

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.