A/T - Overview of Production Changes
89Chevy21Number: 89-192-7A
Section: 7A
Date: June 1989
Subject: 1989 PRODUCT UPDATES FOR 1989 THM 440-T4/HYDRA-MATIC 4T60 TRANSAXLES
Model and Year: 1989 A CAR WITH THM 440-T4 TRANSAXLE
TO: ALL CHEVROLET DEALERS
The Product Information contained in this bulletin describes changes that have occurred on all 1989 THM 440-T4/HYDRA-MATIC 4T60 transaxles. Refer to each section of this bulletin for specific product change information.
This information is an update for 1989 Service Manuals printed prior to December 1, 1988. Use it to update your 1989 Service Manual.
SUBJECT: NEW MATERIAL FOR SIDE COVER TO CHANNEL PLATE GASKET
This section covers a new Side Cover To Channel Plate Gasket (65) that uses a new (Vamac(TM)/cork) latex coated cellulose Gasket (Figure 2). The new Gasket will provide a better seal by reducing the potential of crushing or splitting of the Gasket when the Case Side Cover Pan Nuts (53) are torqued.
Figure 1 - THM 440-T4 (HYDRA-MATIC 4T60)Transaxle Identification Information:
DATE OF PRODUCTION CHANGE: (Figure 1)
November 1, 1988 (Julian Date 306) all THM 440-T4/HYDRA-MATIC 4T60 transaxles are built with the new Gasket.
SERVICE PARTS INFORMATION:
The new Gasket will be available for service once the previous gasket stock has been used up for service. This new Gasket will not be available separately, order the Side Cover Gasket kit package or the Complete Overhaul Repair package.
Part No. Description Model Year/Model Usage
8644902 Pkg. Side Cover Gaskets Kit 1984-89/All
- Gasket, Side Cover to Case
- Gasket, Side Cover to Channel Plate
Parts are currently available from GMSPO.
Figure 3 - New Input Sun/Carrier Bearing Assembly:
SUBJECT: NEW INPUT SUN GEAR TO INPUT CARRIER THRUST BEARING ASSEMBLY
This section covers a new Input Sun Gear to Input Carrier Thrust Bearing Assembly that has increased torque capacity for higher torque engines. The new Input Sun/Carrier Bearing Assembly (661) is 0.38 mm (0.015") thicker and the Input Carrier Assembly (662) Bearing Pocket is machined deeper to accommodate the increased thickness of the new Bearing (Figure 3).
SERVICE ACTION:
The new Input Carrier Assembly (662) will be available for service for all current and past models built after April 1, 1986 (Julian Date 091) (Wider Input Sprag Change).
Figure 1 - THM 440-T4 (HYDRA-MATIC 4T60)Transaxle Identification Information:
DATE OF PRODUCTION CHANGE: (Figure 1)
November 1, 1988 (Julian Date 306) all THM 440-T4/HYDRA-MATIC 4T60 transaxles are built with the new Input Sun/Carrier Bearing Assembly (661) and Input Carrier Assembly (662).
SERVICE PARTS INFORMATION:
Part No. Description Model Year/Model Usage
8668244 Carrier Assembly, Input Complete 1986-89/All
(new)
Parts are currently available from GMSPO.
Figure 2 - Side Cover to Channel Plate Gasket And Wiring Harness:
SUBJECT: NEW WIRING HARNESS TO PREVENT PINCHED/SHORTED CONVERTER CLUTCH SOLENOID WIRES
This section covers a revised wire routing for the Torque Converter Clutch Solenoid (TCC) and 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 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 (TCC) Figure 2, has been added to secure the Wire Conduit (TCC).
SERVICE ACTION:
The new Wire Harness wll not be available for service. When using the old style wire harness ensure the routing will not allow the wires to get pinches between the pump cover and case side cover pan during assembly. This new TCC solenoid wire conduit clip must be used.
Figure 1 - THM 440-T4 (HYDRA-MATIC 4T60)Transaxle Identification Information:
DATE OF PRODUCTION CHANGE: (Figure 1)
November 1, 1988 (Julian Date 306) all THM 440-T4/HYDRA-MATIC 4T6O and THM F-7 transaxles were built using the Wiring Harness and TCC or VCC Clip.
SERVICE PARTS INFORMATION:
When the supply of old style wire harnesses indicated by the asterisk "*" is depleted the new style wire harness will be available.
Part No. Description Model Year/Model Usage
*8662324 Harness Assembly, Wiring 1989/CLH, CPH, CYJ, CZH
8668271 Clip, Wire Conduit (TCC) 1989/All
*Old style wire harness.
Parts are currently available from GMSPO.