SLIPPING OR NO DRIVE/THM325-4L LOOSE OR MISSING CUP PLUG

SLIPPING OR NO DRIVE - 1983 THM 325-4L

Some 1983 Eldorados and Sevilles equipped with THM 325-4L transmissions may experience a slipping or no drive condition. This condition, while not noticed in REVERSE, could be caused by a missing or loose solid cup plug in the input shaft of the foward clutch assembly.

When servicing any 1983 THM 325-4L transmission for a slipping or no drive condition, and the forward clutch assembly shows signs of burning, inspect the housing end of the input shaft which is part of the forward clutch assembly (Figure 1). If the solid cup plug is loose or missing, you will lose apply pressure to the forward clutch piston, and a slipping or no drive condition will result. If the solid cup plug is missing from the feed passage, it must be located before reassembly of the transmission. It could possibly be in the open end of the output shaft (figure 2). Simply tap the end of the output shaft on a table to remove it.

The solid cup plug (P/N 8628145) is serviced separately. Install the cup plug using a 5/16 in. punch, applying Loctite 290 (or equivalent) to the plug before installation. Drive plug into the larger of the two holes until it is 1.0 mm (.039 in.) below the surface.

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.