GRINDING OR GROWLING NOISE IN PARK ON AN INCLINE

TRANSMISSION APPLICATIONS: 3T40, 4T60

TRANSMISSION MODELS:

SUBJECT: INFORMATION ON GRINDING/GROWLING NOISE IN PARK ON AN INCLINE

VEHICLE APPLICATIONS: 1980-91 A,C,E,H,J,K,L,N,P,T,W,X AND U-VAN WITH 3T40 OR 4T60

Bulletin Covers:

This bulletin has been revised to clarify the reason for the noise and to simplify what should be done to eliminate the noise.

Owners of some vehicles equipped with HYDRA-MATIC 3T40 and 4T60 transaxles may comment on a grinding and/or growling noise that is noticeable when standing in "PARK" on a hill or slope with the engine running and the parking brake not applied. Under these conditions, the weight of the vehicle puts a load on the parking pawl which can create a "ground-out" path through the drive axles front struts, springs and spring towers. Normal engine noise can be transmitted to the passenger compartment throught the "ground-out" path.

Owners concerned about this condition should be advised to apply the parking brake prior to shifting into "Park". This is the recommended procedure described in the Owner's Manual. Applying the parking brake first will put the load of the vehicle on the rear brakes rather than on the parking pawl.

Refer the owner to the appropriate Owner's Manual for additional details and instructions.

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.