MODULATOR BUZZ NOISE INSTALL ORIFICE CUP PLUG P/N

MODELS AFFECTED: 1986-87 THM 440-T4 TRANSAXLES BUILT PRIOR TO FEBRUARY 1, 1987 (JULIAN DATE 032)

BULLETIN COVERS: (Figure 1) ---------------- Modulator valve buzz noise can be caused by a missing orificed cup plug in the modulator circuit of the channel plate for transaxles built prior to February 1, 1987 (Julian date 032).

SERVICE ACTION: (Figure 2)

Remove the transaxle from the vehicle and remove the channel plate (404) from the transaxle. Install the orificed cup plug (437) from the service package listed in "Service Parts Information". The cup plug is properly installed at 0.0 - 0.5mm (.020") below the channel plate machined surface and must be staked securely.

SERVICE PARTS INFORMATION:

Service Package Number 8646987 includes the following parts:

- Orificed Cup Plug - Lower Channel Plate Gasket - Upper Channel Plate Gasket - Modulator Port Gasket - Instruction Sheet

SERVICE MANUAL REFERENCE:

Refer to the THM 440-T4 Automatic Transaxle Unit Repair Section in the appropriate model year service manual for repair procedures.

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.