2-1 COASTDOWN CLUNK 200C SERVICE INFORMATION

This Product Service Bulletin supersedes Product Service Bulletin 85-7-117 dated February 28, 1985, which now should be destroyed.

Date of Production Change: (Figure 1)

January 10, 1986, Julian Date 016: Rear internal gear pressed on output shaft.

September 25, 1985, Julian Date 268: 2nd and 3rd clutch exhaust orifice changed.

Service Action (Figures 2 and 3)

To service a 1984 through mid 1986 (prior to Julian Date 016) THM 200C transmission equipped vehicle:

1. Check engine idle speed and set to specifications.

2. Check the rear differential back lash and repair if necessary.

3. On a 1984 or 1985 "BH" model transmission only, remove the primary spring from the governor assembly (Figure 2).

4. On a 1984 or 1985 THM 200C transmission built prior to September 25, 1985 (Julian Date 268), remove the spacer plate and drill the 2nd arid 3rd cliitch exhaust orifice out to 3.57, mm (9/64") (Figure 3). Using a 6.3 mm drill bit, hand chamfer both sides of the hole, slightly, to remove burrs and rough edges.

5. On a THM 200C transmission built prior to January 10, 1986, Julian Date 016, replace the rear internal gear and output shaft with the new pressed an assembly Refer to Service Notes in this bulletin.

6. Upon reassembly of the transmission, reduce the transmission output shaft rear end play to .10 mm - . 38 mm (.004 -.015 inches) by using a thicker selective washer, if required. Do not let rear end play get lower than .004 inches. Transmission damage may result.

Service Parts Information:- (Figure 4)

8633910 Rear internal gear, output shaft assembly.

Service Manual Reference:

Refer to the appropriate model year Service Manual Section.

Service Notes:

All 1984 and 1985 THM 200C models OI, OR and OU already have the pressed on rear internal gear and do not require replacement.

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.