NO REVERSE, FIRST GEAR ONLY OVERHAUL PROCEDURES OUTLINED

VEHICLES AFFECTED: 1979-84 Vehicles Equipped With THM 200, 200-C, 200-4R, 325 and 325-4L Transmissions

1979-1984 Vehicles equipped with THM 200, 200C, 200-4R, 325 and 325-4L transmissions may experience a lack of engagement in reverse, second, third and fourth gear while operating properly in first gear. This condition can be caused by stripped input drum to rear sun gear splines (refer to Figure 1) and does not affect line pressure readings or cause worn clutch plates or bands.

The purpose of this bulletin is to inform technicians performing overhaul procedures for this condition that careful inspection of the input drum splines and planetary gear assemblies is necessary. Spline wear may not be completely obvious during disassembly since the splines may hold with hand torque but not with engine torque.

To inspect the splines properly, remove the snap ring used to retain the input drum to the sun gear shaft and remove the input drum from the sun gear. If any wear is present, replace the sun gear shaft along with the input drum.

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.