LONG 1-2 SHIFT WHEN COLD REPAIR PROCEDURE

Model and Year SOME 1984 AND EARLY 1985 THM 200C

Some 1984 thru early 1985 THM 200C transmissions may experience an occasional long 1-2 shift when cold. To repair this condition, a new spacer plate went into production on September 24, 1984 (Julian Date 268).

When servicing any 1984 thru early 1985 THM 200C transmission built before the above Julian Date, remove the valve body spacer plate. Drill the 2nd and 3rd clutch exhaust orifice out to 3.57mm (9/64") (refer to Figure 1 below). Using a 6.3mm (1/4") drill bit, hand chamfer both sides of the hole, slightly, to remove burrs and rough edges.

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.