TRANSMISSION-QUICK SERV. INFO. MULTIPLE SUBJECTS

THIS BULLETIN CONTAINS MULTIPLE SUBJECTS. PAGE THROUGH TO DESIRED SUBJECT.

GR. 7 NEW DESIGN FORWARD CLUTCH HOUSING - THM 200 AND 200C ALL

BEGINNING EARLY IN THE MODEL YEAR, A PRODUCTION TRIAL RUN BEGAN ON A NEW DESIGN FORWARD CLUTCH HOUSING AND CHECK VALVE ASSEMBLY. THE NEW DESIGN FORWARD CLUTCH HOUSING WILL HAVE A STEEL WALL STAMPED INTO THE HOUSING WHICH WILL SURROUND AND PROTECT THE CHECK VALVE ASSEMBLY. SEE ILLUSTRATION BELOW.

THE NEW DESIGN CHECK VALVE ASSEMBLY WILL BE SHORTER IN LENGTH THAN THE PAST DESIGN.

ALL PARTS INVOLVED IN THIS NEW DESIGN ARE COMPLETELY INTERCHANGEABLE AND REQUIRE NO SERVICE PROCEDURE CHANGES.

GR. 7 DIAGNOSING THE 200-4R TRANSMISSION

WHEN DIAGNOSING THE 200-4R TRANSMISSION FOR OPERATION, THE TORQUE CONVERT CLUTCH CAN BE DISCONNECTED; HOWEVER, WITH THE TRANSMISSION IN FOURTH GEAR AND THE CONVERTER CLUTCH NOT APPLIED, THE HEAT BUILD UP DEVELOPED BY THE CONVERTER'S FLUID COUPLING CAN DECREASE THE LIFE OF THE OIL DUE TO FASTER OIL OXIDATION.

WHEN DRIVING THE CAR AND PULLING A TRAILER WITH THE CONVERTER CLUTCH DISCONNECTED AND THE TRANSMISSION IN FOURTH GEAR, HIGH OIL TEMPERA- TURES CAN BE GENERATED WHICH CAUSE RAPID OIL DETERIORATION AND CAN DAMAGE THE TRANSMISSION.

GR. 7 THM OIL PUMP BODY TO GEAR FACE CLEARANCE SPECIFICATIONS

THE RECOMMENDED OIL PUMP BODY TO GEAR FACE CLEARANCE SPECIFICATION HAS BEEN CHANGED FOR THE THM 400, 325, 200, AND 200C TRANSMISSIONS.

MODEL OIL PUMP BODY TO GEAR FACE CLEARANCE SPECIFICATION

THM 400 .018/.066MM (.0007/.0026 INCH) THM 325 .030/.069MM (.0012/.0027 INCH) THM 200 & 200C .018/.066MM (.0007/.0026 INCH)

PLEASE NOTE THE CHANGES IN YOUR SERVICE MANUALS, FOR ALL MODEL YEARS.

GR. 7 USE OF LOCKTITE 515 ON THM 400 CASE EXTENSION GASKET

BEGINNING MID-NOVEMBER, 1980, MOST MODELS OF THE THM 400 TRANSMISSION WERE BUILT WITH LOCKTITE 515 ON THE CASE EXTENSION GASKET.

FOR SERVICE APPLICATIONS, DO NOT USE LOCKTITE ON THE CASE EXTENSION GASKET. FOLLOW NORMAL SERVICE PROCEDURE AND REASSEMBLE WITH DRY GASKET.

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.