New Reverse Servo Apply Pin Selection Chart
SERVICE MANUAL REFERENCERefer to the Transaxle Hydraulic Diagnosis and Transaxle Unit Repair Sections in your 1989 Service Manual for changes shown in this bulletin.
TRANSAXLE APPLICATIONS: SUBJECT:
1989 THM 440-T4 (ME9) New Reverse Servo Apply Pin
Selection Chart
TRANSAXLE MODELS: VEHICLE APPLICATIONS:
All THM 440-T4 Models A, C, H, E, W, Cars
FIGURE 2 - REVERSE BAND APPLY PIN:
CHANGE TO ASSEMBLY COMPONENT (Figure 2)
The reverse servo apply pin (551) selection chart has been changed for the 1989 model year to eliminate the longest and the two shortest of the selection set. The 1989 transaxle calibrations require a new selection set for the THM 440-T4 Transaxles.
SERVICE ACTION
When servicing a past model THM 440-T4 transaxle use the proper year servo apply pin selection chart.
FIGURE 2 - REVERSE BAND APPLY PIN:
SERVICE PARTS INFORMATION
Reference new reverse servo apply pin selection chart, Figure 2.
10 Plate 3rd Clutch Pack
SERVICE MANUAL REFERENCE
This product change information is shown in the THM 440-T4 Automatic Transaxle Unit Repair section of your 1989 Service Manual.
TRANSAXLE APPLICATIONS: SUBJECT:
1989 THM 440-T4 (ME9) 10 Plate 3rd Clutch Pack
TRANSAXLE MODELS: VEHICLE APPLICATIONS:
All THM 440-T4 A, C, H, E, W, Cars
FIGURE 3 - INPUT CLUTCH ASSEMBLY:
FIGURE 4 - 3RD CLUTCH PLATE ASSEMBLY:
FIGURE 5 - INPUT CLUTCH PISTON:
FIGURE 6 - 3RD CLUTCH PISTON HOUSING ASSEMBLY:
FIGURE 7 - 3RD CLUTCH PISTON SEAL ASSEMBLY AND RETAINER & BALL ASSEMBLY:
FIGURE 8 - 3RD ROLLER CLUTCH RACE:
FIGURE 9 - 3RD CLUTCH SPRING RETAINER & GUIDE ASSEMBLY:
CHANGE TO ASSEMBLY COMPONENT (Figures 3, 4, 5, 6, 7, 8, and 9)
A new 10 plate 3rd clutch pack (640) is used to replace the 8 plate 3rd clutch pack for all 1989 THM 440-T4 transaxles. The two extra plates were added for new higher torque engine applications. For this change to be implemented the following parts were modified:
- 3rd clutch plate (fiber one side) I.D. and O.D. splines, (Figure 4) are thinner by 0.15 mm (0.006"). The fiber material is the same thickness only the steel part of the plate was made thinner.
- Input clutch piston (630) cutouts for the 3rd clutch plates are 6.35 mm (0.25") deeper so the piston travel will clear the increased thickness of the 3rd clutch plate pack. (Figure 5)
- 3rd clutch piston housing (633) has decreased in overall size. (Figure 6)
- 3rd clutch piston (637) seal (635) is now molded to the piston (802) (Figure 7).
- 3rd roller clutch outer race (645) is wider by 0.83 mm (0.033") to accommodate the two extra plates. (Figure 8) Notice: The rollers have not changed in width.
- 3rd clutch spring retainer and guide assembly (638) cutout is 1.1 mm (0.043") deeper for 1989. This allows sufficient clearance for the relocated retainer and ball assembly that is part of the new 3rd clutch piston seal assembly and retainer and ball assembly (802). (Figure 9)
SERVICE ACTION
When servicing a 1984 through 1988 THM 440-T4 transaxle, you must use the previous 3rd clutch pack assembly as shown in the Service Parts Information section below. DO NOT interchange individual components with previous model years or a misbuild will occur. The 1989 input clutch apply piston assembly (630) and 1989 3rd clutch spring retainer and guide assembly (638) are the only components of the 10 plate 3rd clutch pack that can service prior model years.
SERVICE PARTS INFORMATION
Part No Description Model Year - Model Usage
8646938 Plates, 3rd Clutch (fiber 1987-88 All 87 models, 8BJH,
one side) (8 plates) (640) 8BKH, 8BRH, 8BTH, 8BYH,
8FBH, 8FCH, 8FJH, 8FSH,
8VXH
8662954 Plates, 3rd Clutch (fiber 1989 - All Models
one side with wave plate)
(10 plates) (640)
8668295 Piston Asm. Input Clutch 1984-89 All Models
Apply (630)
Parts (listed above) are currently available from GMSPO.
8662927 Plates, 3rd Clutch (Fiber 1988 8AAH, 8ABH, 8AFH, 8AJH
one side with wave plate) 8ANH, 8ATH, 8CFH, 8CMH
8GRH, 8CTH, 8CWH, 8CXH
Parts are expected to be available (for part number 8662927) on 11/28/88. Until then normal part orders will not be accepted by GMSPO. Only verifiable emergency VIP orders will be accepted. SPO will make every effort to obtain parts. All parts will be placed on 400 control to waive VIP surcharges. However, the part will be shipped premium transportation at dealer's expense. All other order types will be cancelled as incorrectly ordered while the 400 control is in place.
8656310 Housing 3rd Clutch 1984-88 All Models
Piston (633)
8668359 Housing, 3rd Clutch 1989 All Models
Piston 633)
8644919 Piston, 3rd Clutch (637) 1984-88 All Models
8668453 Seal Asm. and Retainer and 1989 All Models
Ball Asm., 3rd Clutch Piston (802)
8662676 Roller Asm. Comp. - 3rd 1984-88 All Models
Clutch (645)
8668367 Roller Asm. Comp. - 3rd 1989 All Models
Clutch (645)