A/T - Oil Pump Rotor & Slide Update
Bulletin 84-7200-3Date April '84
Ref. No. 84-209-7200
SUBJECT: SERVICE PRDCEDURE FOR REPAIR OR REPLACEMENT OF THE OIL PUMP ROTOR AND SLIDE
MODELS AFFECTED: ALL THM 200-4R TRANSMISSIONS
Beginning mid November, 1983, service parts became available to service the oil pump rotor and slide of the pump body assembly, on all THM 200-4R transmissions. This service procedure on all THM 200-4R transmissions must be followed to assure proper end clearance on the oil pump rotor and slide.
SERVICE PROCEDURE:
NOTICE: DO NOT attempt to service the oil pump rotor if either the pump body pocket or pump body cover surfaces are scored. Servicing of the oil pump rotor and slide should be performed ONLY if the selective pump rotor, or the slide show wear.
FIGURE 1 - THM 200-4R - OIL PUMP BODY ASSEMBLY:
1. Disassembly of The Oil Pump
A. Disassemble the oil pump body assembly following procedures outlined in the service manual. Figure 1 is an illustration of the THM 200-4R oil pump body assembly.
FIGURE 2 - GAUGING ROTOR:
2. Selecting the Pump Rotor and Slide
A. Use a micrometer to measure the original pump rotor and slide thickness accurately (Figure 2 ). To obtain the most accurate reading, measure on flat undamaged surfaces.
B. Using the original part measurement, order replacement parts according to the following selective charts.
CHART NUMBER 1
SELECTIVE PUMP ROTOR IDENTIFICATION
PART NUMBER THICKNESS IN MM. THICKNESS IN INCHES
8634091 17.948 - 17.961 0.7066 - 0.7071
8634092 17.961 - 17.974 0.7071 - 0.7076
8634093 17.974 - 17.987 0.7076 - 0.7081
8634094 17.987 - 18.000 0.7081 - 0.7086
8634095 18.000 - 18.013 0.7086 - 0.7091
CHART NUMBER 2
SELECTIVE PUMP SLIDE IDENTIFICATION
PART NUMBER THICKNESS IN MM. THICKNESS IN INCHES
8634081 17.948 - 17.961 0.7066 - 0.7071
8634082 17.961 - 17.974 0.7071 - 0.7076
8634083 17.974 - 17.987 0.7076 - 0.7081
8634084 17.987 - 18.000 0.7081 - 0.7086
8634085 18.000 - 18.013 0.7086 - 0.7091
NOTE: The replacement part will provide the same clearance that the oil pump assembly was originally built with the proper end clearance specification is 0.020 to 0.050 mm. or (.0008") to (.002").
C. Hone both sides of the replacement rotor and slide to remove burrs, and measure the replacement parts with a micrometer to assure proper selection.
NOTE: Incorrect rotor selection could result in a damaged oil pump assembly and/or low oil pressure. Incorrect slide selection could result in incorrect line pressure.
3. Assembly:
A. Reassemble the oil pump assembly following procedures outlined in the service manual.
B. After assembling the oil pump onto the transmission install the converter and check for proper rotor and slide clearance by turning the converter. The converter should turn freely. If the converter does not turn freely, recheck the pump rotor and slide selection.
C. Install the transmission into the vehicle.
D. Before road testing the vehicle, install an oil pressure gauge into the transmission and check oil pressure. Refer to the service for oil pressure specifications.