HIGH PITCH WHINE NOISE 1ST,2ND & REVERSE-1983 MODEL 200C/200R

Some 1983 Deville and Brougham vehicles equipped with THM 200-4R transmissions may experience a noise condition during vehicle operation from a standing start that sounds like a high pitched whine. This noise condition may be coming from the front internal gear assembly of the compound planetary gearset, the torque converter or the hydraulic pump.

In diagnosing this condition, if the noise is noticeable in DRIVE with the brake applied, the vehicle stationary and the engine at approximately 1500 RPM, the cause could be a torque converter bearing noise or an oil pump cavitation noise. Use service procedures for checking torque converter end play in Section 7A of the 1983 Service Information Manual to isolate if the torque converter or oil pump is the cause of the condition.

If the whine noise is only noticeable when driving the car in first, second or reverse gear ranges, the most likely cause would be mismachined teeth on the front internal gear. When servicing a 1983 THM 200-4R transmission for this whine type nolse condition and the cause has been diagnosed to be the front internal gear, replace it with P/N 8630909.

For warranty purposes, use labor Operation Number K7250 at 4.0 hours to replace the front internal gear.

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.