A/T - Buzzing Noise on Shutdown

Number: 93-28-7A
Section: 7A
Date: OCT. 1992
Corporate Bulletin No.: 277141
ASE No.: A2

Subject:
BUZZING NOISE ON ENGINE SHUTDOWN

Model and Year:
1993 C/K, S/T TRUCKS AND 1993 G AND WL VANS WITH 4L60-E AUTOMATIC TRANSMISSION

TRANSMISSION APPLICATIONS:
1993 HYDRA-MATIC 4L60-E (M30)

TRANSMISSION MODELS:
All

SUBJECT:
Pressure Regulator Valve Buzz

VEHICLE APPLICATIONS:
C/K, S/T - Trucks G, M, L - Vans

CONDITION:

Some 1993 vehicles equipped with the HYDRA-MATIC 4L60-E transmission may exhibit a buzzing noise coming from the transmission on engine shutdown.

CAUSE:

The buzzing noise may be a result of the pressure regulator valve oscillating due to oil pressure instability during engine shutdown.

CORRECTION:





A new pressure regulator valve (III. 216) has been released which will improve the oil pressure stability at lower RPM.

SERVICE PARTS INFORMATION:

Description Part Number

Valve, Pressure Regulator (111.216) 8684049

Part numbers are for Reference Only.
Check with your Parts Department for latest information.

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.