For 1990-2009 cars

# TCC DOUBLE BUMP ENGAGEMENT VACUUM SWITCH

#### VEHICLES AFFECTED: 1984 'A' And 'X' Series Vehicles Equipped With 2.8L Non-Closed Loop Emission System And 125-C Transmission

A condition has been identified with 1984 2.8L 'A' and 'X' cars equipped with THM 125-C transmissions whereby transmission converter clutch may engage and immediately disengage. Depending upon operating conditions, the converter clutch may again engage giving an objectionable 'double bump' feel to the converter clutch engagement.

To correct this condition, replace the transmission converter clutch engagement vacuum switch P/N 14014519 (calibration 2 1/2 - 7 in. Hg.) with a new switch P/N 14081973 (calibration 2 - 6 in. Hg.). Note that the driver can still cause the reaction to occur, but it is now moved out of the normal vehicle operating range. Converter clutch engagement speed is not affected.

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.