Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
Valve Body: All Technical Service Bulletins
A/T - New Control Valve Assembly Elimination of TCC Bore
GMC NUMBER:
89-T-25
GROUP:
7A - Automatic Transmission
DATE:
February, 1989
CORPORATE
NUMBER:
877156
SUBJECT:
NEW CONTROL VALVE ASSEMBLY - ELIMINATION OF TCC BORE
MODELS:
1982-89 C1, C2, K1, K2, R1, V1, S1, T1, G1, G2, G3, MW/700R4
Figure No. 1
BULLETIN COVERS: (Figure No.1)
Service information for new THM 700- R4/HYDRA-MATIC 4L60 control valve assembles. The new control valve assembly will no longer have the
TCC bore, and now contains a "notch" in the channeling allowing 2nd Clutch oil into the TCC circuit (refer to Figure No. 1). The TCC bore, in the past,
has housed either the converter dutch throttle valve and sleeve or the converter clutch bore plug. The converter clutch throttle valve was used on models
that had non-ECM controlled TCC apply. The converter clutch bore plug was used on models that had ECM controlled TCC apply. Starting with 1989
production, all THM 700-R4(HYDRA-MATIC 4L60 models are ECM controlled TCC apply. Since there are no current produdion models using the
converter dutch throttle valve, the TCC bore is not . needed and has been elminated.
