A/T - No Drive and Reverse

Number 83-T-33 Section 7 Date 05/83

Subject: NO DRIVE AND REVERSE - 1982-1983 THM 700-R4 TRANSMISSION

If a THM 700-R4 transmission experiences a loss of drive and reverse, a possible cause for this condition may be a broken or cracked oil pump rotor.

The oil pump rotor can be broken or cracked by:

1. Not engaging the converter hub slots completely into the lugs of the oil pump rotor during assembly.

2. Allowing the converter to hit on something, such as the floor or table, while handling the transmission assembly.

3. Dropping an oil pump rotor on the floor while handling.

SERVICE PROCEDURE

When servicing any THM 700-R4 transmission for a no drive or reverse condition, install an oil pressure gage to verify a broken oil pump rotor. If zero line pressure is obtained, the oil pump rotor could be cracked. If the oil pump rotor is broken or cracked, proceed as follows (refer to Service Manual if necessary):

A. If the oil pump rotor is cracked but not broken, replace the oil pump body (see chart for part number). If the oil pump cover assembly is scored or damaged, replace it also.

PART
YEAR PART MODELS NUMBER
All Oil Pump Body Assembly All 8642986
All Package Overhaul Seals & Gaskets All 8642953
All Package, Overhaul - Complete All 8642954
1982 Oil Pump Cover Assembly M6, MH, TN, TP 8647190
1982 Oil Pump Cover Assembly All Other Models 8647189
1983 Oil Pump Cover Assembly TS, TZ, T8, TP, NH, VJ, TL, YH 8647190
1983 Oil Pump Cover Assembly T2, VA, YN, ML, MP, MS, T7, YF, 8647189
YG, PQ, YP, YK, Y9, TC, MB, MC, 8647190
MJ, VN, TE, TH, TK, MD, ME, MK, 8647189
MW, VH


B. If the oil pump rotor is broken, you must:
1. Replace the converter. Do not reuse the converter due to possible metal particle contamination.
2. Flush the transmission oil cooler and lines.
3. Disassemble and clean the valve body assembly.
4. Completely disassemble, clean and inspect all internal components. Replace any damaged or worn parts.
5. Clean the transmission case thoroughly. Make sure all bores and channels are free of dirt or foreign material.
6. Inspect all bushings for scoring or damage. Replace if necessary.
7. Replace the oil pump cover and body (refer to chart for part number).
8. Reassemble the transmission following Service Manual procedures.