BUZZING NOISE AT IDLE (INSTALL PRESSURE REGULATOR VALVE)

SUBJECT: BUZZING NOISE AT IDLE

MODEL and YEAR: 1982-93 CAPRICE, CAMARO AND CORVETTE 1982-93 C/K, R/V, S/T, M/L AND G TRUCKS WITH 4L60 AUTOMATIC TRANSMISSION

TRANSMISSION APPLICATIONS:

1982-1993 HYDRA-MATIC 4L60 (MD8)

TRANSMISSION MODELS:

All

SUBJECT: ------- Pressure Regulator Valve Buzz

VEHICLE APPLICATIONS:

B, D, F, Y - Cars C/K, R/V, S/T - Trucks G, M, L - Vans

CONDITION:

--------- Some 1982-1993 vehicles equipped with a HYDRA-MATIC 4L60 transmission may have a buzzing noise coming from the transmission when the vehicle is at idle. The buzzing noise may be noticed more when the vehicle is in reverse at idle.

CAUSE:

----- The buzzing noise may be a result of pressure regulator valve oscillating due to oll pressure instability at lower idle RPM.

CORRECTION:

---------- A new pressure regulator valve (III. 218) has been made which will improve the oil pressure stability at lower RPM.

SERVICE PARTS INFORMATION:

Description Part Number ----------- ----------- Valve, Pressure Regulator (III. 218) 8684048

Labor Operation No.: K6550 Valve, Pressure Regulator-R&R or Replace

Use the appropriate labor time in the labor time guide.

Parts are currently available from GMSPO.

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.