K 2500 Truck 4WD V8-379 6.2L DSL VIN C FI (1989)
Case: Technical Service Bulletins
A/T - New Case, 2nd, 3rd, 4th Pressure Taps Removed
GMC NUMBER:
89-T-47
GROUP:
7A - Automatic Transmission
DATE:
April, 1989
CORPORATE
NUMBER:
977107
SUBJECT:
NEW CASE ASSEMBLY - REMOVAL OF 2ND, 3RD AND 4TH CLUTCH PRESSURE TAPS
MODELS:
1982-89 700-R4,C,G,K,M,R,S,T,V TRUCKS
Figure 1 - Removal Of 2nd, 3rd And 4th Clutch Pressure Taps
Bulletin Covers:
(Figure 1)
Service information for new THM 700- R4/HYDRA-MATIC 4L60 Case assembles. The new case win no longer have the 2nd, 3rd or 4th clutch pressure
taps. Mainline pressure tap remains unchanged. The clutch pressure taps require case bosses to bring the channeling to the exterior of the case and
provide an area to tap and plug the pressure ports. The casting process necessary to provide the case bosses and channeling increase the chance of case
porosity in those areas. By removing the clutch pressure taps, the casting can be changed to reduce incidences of case porosity and leaks.
Figure 2 - THM 700-R4/HYDRA-MATIC 4L60 Transmission Identification Information
Date of Production Change:
(Figure 2)
Starting December 2, 1988 (Julian Date 337) all THM 700-R4/HYDRA-MATIC 4L60 transmissions were built without drilling and tapping the 2nd, 3rd
