A/T - New Control Valve Assembly Elimination of TCC Bore
89chevy13GMC 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.
Figure No. 2:
DATE OF PRODUCTION CHANGE:
(Figure No. 2)
Starting on November 14,1988, Julian Date 319, all THM 700-R4/HYDRA-MATIC 4L60 models use the new control valve assemblies.
SERVICE ACTION:
Past THM 700-R4 control valve assemblies that used the converter clutch throttle valve and sleeve (non-ECM controBed TCC apply) wfll be maintained for service. Service control valve assemblies containing the converter dutch throttle valve and sleeve will continue to be available through GMSPO. The THM 700-R4AlMRA-MATIC 4L60 control valve assemblies build with the converter clutch bore plug (ECM controlled TCC apply) are serviceable with the new control valve assembly. The new service control valve assembhes (no TCC bore) will supersede the appropriate applications as current service stock is depleted.