A/T - Updated Diagnostics & Description
89Oldsmobile09SUBJECT: PRELIMINARY DIAGNOSIS AND DESCRIPTION OF NEW TRANSAXLE
MODELS/YEARS: 1989 CUTLASS SUPREME EQUIPPED WITH 3.1L
ENGINE AND THM 440-T4/HYDRA-MATIC 4T60 TRANSAXLE (RPO - ME9)
NUMBER: 89-T-78
CORP. REF. NO: 977118R
DATE: June 1989
SECTION: 7A
Figure 1 - HYDRA-MATIC 4T60 Transaxle Identification Information:
TRANSAXLE MODELS: OCHH, OCJH, OYKH, OYLH
CHANGE TO ASSEMBLY COMPONENTS: (Figure 1)
Four early 1990 HYDRA-MATIC 4T60 transaxle models used in 1989 Cutlass Supremes require new Shift Speed and Oil Pressure Chart and Wiring Diagram.
SERVICE MANUAL REFERENCE:
Reference the following information when servicing a 1990 model. All other instructions and procedures are the same as published in 1989 Service Manuals. Refer to the appropriate Automatic Transaxle Diagnosis section in the 1989 Service Manual for information not covered in this publication.
Figure 2 - Shift Speed Chart:
Figure 3 - Preliminary Check Procedure:
SUBJECT: New Shift Speed And Oil Pressure Charts
CHANGE TO ASSEMBLY COMPONENTS: (Figures 2 and 3)
The 1990 HYDRA-MATIC 4T60 transaxle shift speed and oil pressure charts have been changed for the new 3.1L engines.
SERVICE ACTION:
Reference the new shift speed and oil pressure charts when servicing the 1990 OCHH, OCJH, OYKH, OYLH models.
SERVICE MANUAL REFERENCE:
Reference the 1989 Service Manual for other information not contained in this bulletin.
Figure 4 - Wiring Diagram:
SUBJECT: New Wiring Harness to Prevent Pinched/Shorted Converter Clutch Solenoid Wires
(Figure 4)
A revised wire routing for the Torque Converter Clutch Solenoid (TCC) requires a new Wiring Harness. The TCC wires are now routed straight down from the Engine Wire Harness Connector to the TCC Solenoid instead of going around the Oil Pump Body. This change reduces the possibility of the TCC wires becoming pinched/shorted between the Pump Cover and the Case Side Cover Pan during assembly. For this change to occur, a Wire Conduit Clip, for the TCC solenoid has been added to secure the Wire Conduit (TCC).
SERVICE ACTION:
The new Wire Harness will not be available for service. Order the old style wire harness to service these new models. When using the old style wire harness ensure the routing will not allow the TCC wires to get pinched between the pump cover and case side cover pan during assembly. The new TCC solenoid wire conduit clip must be used with the new wire harness.
SERVICE PARTS INFORMATION:
When the supply of the old style wire harness indicated by the asterisk "*" is depleted, the new style wire harness will be available.
Part No. Description Model Year Model Usage
*8662852 Harness Assembly, Wiring 1990 OCHH, OCJH,
OYKH, OYLH
8668271 Clip, Wire Conduit (TCC) 1990 All
*Old style wire harness
Parts are currently available from GMSPO.