S10/T10 P/U 4WD L4-119 1.9L VIN A 2-BBL (1983)
Fluid Pump: All Technical Service Bulletins
A/T Oil Pump Seal Assembly - Leaking
Number:
83-T-59
Section:
VIIc
Date:
June, 1983
Subject:
OIL PUMP SEAL ASSEMBLY LEAKING - THM 700-R4 ALL
FIGURE 1 - OIL PUMP BODY
TO:
ALL CHEVROLET DEALERS
Beginning March 7, 1983, all THM 700-R4 transmissions were built with a revised oil pump body (P/N 8642986). As shown in Figure 1, the
oil drainback passage in the revised pump body connects with one of the core slots. This design change allows for more effective oil
drainback, thereby relieving pressure under the oil seal assembly.
FIGURE 2 - CUT-AWAY VIEW OF DRAINBACK PASSAGE
SERVICE INFORMATION
When servicing a THM 700-R4 built prior to this change which either: (1) pushes the oil seal assembly out of the oil pump body or (2) forces