A/T - Buzzing Noise at Idle
Bulletin: 93-74L60-2Date: Nov., '92
Ref.No.: 93-36-74L60
Corp.Ref.No.: 277142
SUBJECT:
BUZZING NOISE AT IDLE (INSTALL NEW PRESSURE REGULATOR VALVE)
MODELS AFFECTED:
1991-93 ROADMASTERS
CONDITION:
Some 1991-93 Roadmasters 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 oil pressure instability at lower idle RPM.
CORRECTION:
A new pressure regulator valve has been released which will improve the oil pressure stability at lower RPM.
SERVICE PARTS INFORMATION:
Description Part Number
Valve, Pressure Regulator 8684048
WARRANTY INFORMATION:
Labor Operation No.:
K6550 Valve, Pressure
Regulator--R&R or Replace
Parts are currently available from GMSPO.