LOSS OF DRIVE/NO REVERSE 200 TRANSMISSION

Subject: LOSS OF DRIVE AND/OR NO REVERSE - 1982 THM 200C TRANSMISSION

Some 1982 THM 200C transmissions may experience a loss of drive and/or no reverse condition. A possible cause for this condition may be a broken or cracked drive or driven oil pump gear.

When servicing any 1982 THM 200C transmission for a loss of drive and/or no reverse condition, and the oil pump gears are broken or cracked, the transmission must be thoroughly cleaned and inspected. Refer to the following repair procedure.

REPAIR PROCEDURE

1. Remove and disassemble the entire transmission unit.

2. Replace the converter. Do not use the old converter, due to metal particle contamination.

3. Flush the transmission cooler lines. Dirt and foreign material may have contaminated the cooler lines.

4. Disassemble the control valve assembly, carefully following the procedures outlined in the Service Manual. Flush and inspect all the bores, valves, springs, bushings, etc., for dirt and foreign material. Replace if necessary.

5. Flush the transmission case thoroughly with solvent. Make sure all bores, channels and passages are free of dirt and foreign material.

6. Disassemble the direct, forward and low/reverse clutch assemblies. Clean and inspect parts. Replace composition faced clutch plates if scored.

7. Clean and inspect all pistons, gears, shafts and remaining internal parts. Replace all seals and gaskets. Order service overhaul kit (part number 8638919).

8. Inspect all bushings for scoring or damage. Replace if necessary.

9. Reassemble all internal components following Service Manual procedures.

10. Replace the pump body assembly (part number 8632944) and pump cover assembly (part number 8633958).

11. Replace the oil screen assembly with service part number 8632949.

12. Reassemble the transmission following the Service Manual procedures. DO NOT USE THE OLD GASKETS AND SEALS, USE ITEMS CONTAINED IN THE OVERHAUL KIT.

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.