NEW PRODUCT INFORMATION PRODUCTION CHANGES 440-T4
SUBJECT: 1988 THM 440-T4 (ME9) 1988 NEW PRODUCT INFORMATION
VEHICLES AFFECTED: ALL 1988 A, C, H, E, K, and W Models ALL MODELS
BULLETIN COVERS:
New Product Information on all 1988 model THM 440-T4 transaxles. The information contained in this bulletin describes changes that occurred at the Start Of Production (SOP) for 1988 THM 440-T4 transaxles. Refer to each section of this bulletin for specific product change information.
DATE OF PRODUCTION CHANGE:
At the Start Of Production, 1988 THM 440-T4 transaxles were produced with the product changes listed in this bulletin.
SERVICE MANUAL REFERENCE:
Refer to the Transaxle Hydraulic Diagnosis and Transaxle Unit Repair Sections in your 1988 service manual for changes shown in this bulletin. These product changes have been identified by an asterisk (*) on the table of contents page if the change affects transaxle diagnosis, disassembly, or assembly procedures. ----------------------------------------------------------------------------
TRANSAXLE APPLICATIONS: SUBJECT: ---------------------- ---------------- 1988 THM 440-T4 (ME9) New Manual Shaft
TRANSAXLE MODELS: VEHICLE APPLICATIONS: ----------------- All A, C, H, E, K, W Cars
CHANGE TO ASSEMBLY COMPONENT: (Figure 2) ----------------------------------------- A new manual shaft (702) that is 7mm (.276") longer is used on all 1988 THM 440-T4 transaxles. This longer manual shaft was first used on two 1987 model THM 440-T4 transaxles (7ADH, 7AHH) and is not interchangeable with the shorter manual shaft.
SERVICE ACTION
When servicing a 1987 or 1988 model THM 440-T4 transaxle use the proper manual shaft as listed in the Service Parts Information section below.
SERVICE PARTS INFORMATION:
Part Number Description Model Year Usage ---------- --------------------------- ------------------- 8646946 Package, Manual Shaft and Seal 1988 - All Models (1) Shaft, Manual 1987 - 7ADH, 7AHH (1) Seal, Manual Shaft Models Only 8644923 Package, Manual Shaft and Seal 1987 - All Models Except (1) Shaft, Manual 7ADH, 7AHH (1) Shaft, Manual Shaft
SERVICE MANUAL REFERENCE:
This product change does not affect diagnosis, disassembly or assembly procedures for 1988 THM 440-T4 transaxles and is not shown in the 1988 THM 440-T4 Unit Repair Section of your service manual. -----------------------------------------------------------------------------
TRANSAXLE APPLICATIONS: SUBJECT: ----------------------- ------------------------- 1981 THM 440-T4 (ME9) New Reverse Reaction Drum
TRANSAXLE MODELS: VEHICLE APPLICATIONS: ----------------- ---------------------- All A, C, H, E, K, W Cars
CHANGE TO ASSEMBLY COMPONENT: (Figure 3) ----------------------------------------- A new reverse reaction drum (659) for all 1988 THM 440-T4 transaxles. The change to the reverse reaction drum is identified by a chamfer on both ends of the drum.
SERVICE ACTION:
When servicing a 1987 or 1988 THM 440-T4 transaxle the new reverse reaction drum (659) may be used. When servicing a 1984 through 1986 THM 440-T4 transaxle you must use the previous reverse reaction drum as shown in the Service Parts Information section below.
SERVICE PARTS INFORMATION:
Part Number Description Model Year Model Usage ---------- -------------------- ---------- ------------ 8661092 Drum, Reverse Reaction 1987-1988 All Models
8656612 Drum, Reverse Reaction 1984-1986 All Models
SERVICE MANUAL REFERENCE:
This product change does not affect diagnosis, disassembly or assembly procedures for 1988 THM 440-T4 transaxles and is not shown in the 1988 THM 440-T4 Unit Repair Section of your service manual.
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TRANSAXLE APPLICATIONS: SUBJECT: ------------------------ -------- 1988 THM 440-T4 (ME9) New 3rd Clutch Wave Plate
TRANSAXLE MODELS: VEHICLE APPLICATIONS: ------------------ ---------------------- AAH, ABH, AFH, ANH, ATH, CFH, CMH, A, C, E, K, W Cars With CRH, CTH, CWH, CXH 2.8L Or 4.5L Engines
CHANGE TO ASSEMBLY COMPONENTS: (Figure 4) ------------------------------------------- A new 3rd clutch plate (640A), waved instead of a flat steel plate, is used in some 1988 A, C, E, K, and W cars equipped with 2.8L or 4.5L engines and a THM 440-T4 transaxle. All other 1988 model transaxles continue to use the previous design flat steel plate as part of the assembly. The new 3rd clutch plate (waved) cushions the apply of the 3rd clutch.
SERVICE ACTION:
When servicing the 3rd clutch assembly on the following 1988 THM 440-T4 transaxle models: AAH, ABH, AFH, ANH, ATH, CFH, CMH, CRH, CTH, CWH, CXH, use the 3rd clutch plate (waved) listed in the Service Parts Information section below. This new plate must not be used to service prior model year transaxles.
SERVICE PARTS INFORMATION:
Part Number Description ----------- ----------------- 8656645 Plate, 3rd Clutch (waved)
SERVICE MANUAL REFERENCE:
This product change information is shown in the THM 440-T4 Automatic Transaxle Unit Repair section of your 1988 Service Manual. Other product changes that are new for 1988 model THM 440-T4 transaxles have been identified by an asterisk (*) in the Table of Contents.
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TRANSAXLE APPLICATIONS: SUBJECT: ----------------------- -------- 1988 THM 440-T4 (ME9) New 2nd Clutch Switch
TRANSAXLE MODELS: VEHICLE APPLICATIONS: ------------------ --------------------- BJH, BKH, BRH, BTH, BYH C, E, H Cars With 3800 Engines
CHANGE TO ASSEMBLY COMPONENTS: (Figure 5) ------------------------------------------- A new 2nd clutch switch (normally closed switch) with a new wiring harness assembly (48) for some 1988 C, E and H cars equipped with a 3800 engine and THM 440-T4 transaxle. When the transaxle shifts into second gear, the switch "opens" to signal the Electronic Control Module (ECM).
SERVICE ACTION:
When servicing a 1988 BJH, BKH, BRH, BTH or BYH model THM 440-T4 transaxle, only use the new wiring harness assembly and pressure switch assembly listed in the Service Parts Information section below. Also note in the wiring diagram (Figure 5) that a five PIN electrical connector is used on these models.
SERVICE PARTS INFORMATION:
Part Number Description ---------- ------------ 8658040 Switch Assembly, Pressure (2nd Clutch)
8662852 Harness Assembly, Wiring
SERVICE MANUAL REFERENCE:
This product change information is shown in the THM 440-T4 Automatic Transaxle Hydraulic Diagnosis section of your 1988 Service Manual. Other product changes that are new for 1988 model THM 440-T4 transaxles have been identified by an asterisk (*) in the Table of Contents.
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TRANSAXLE APPLICATIONS: SUBJECT: ----------------------- --------- 1988 THM 440-T4 (ME9) New Final Drive Assembly; New Output Shaft; And New Final Drive Sun Gear Shaft
TRANSAXLE MODELS: VEHICLE APPLICATIONS: ------------------ ---------------------- AAH, ABH, AFH, ANH, ATH C, E, K Cars
CHANGE TO ASSEMBLY COMPONENTS: (Figure 6) ------------------------------------------- A new final drive assembly (679), new output shaft (565) and new final drive sun gear shaft (669) for 1988 C, E and K cars equipped with 4.5L engines and a THM 440-T4 transaxle. The new final drive assembly (679) has larger differential side gears (688) and larger differential pinion gears (686). To accommodate the larger gears, the output shaft (565) was lengthened by .73mm (.029"). The final drive sun gear shaft (669) was also changed by adding two additional lube holes for increased lubrication to the final drive.
SERVICE ACTION:
When servicing a 1988 AAH, ABH, AFH, ANH or ATH model THM 440-T4 transaxle use the parts listed in the Service Parts Information section below. DO NOT interchange these components with other model THM 440-T4 transaxles or a misbuild will occur.
SERVICE PARTS INFORMATION:
Part Number Description 1988 Model Usage --------- ------------------ ------------------- 8662922 Package, Final Drive AAH, ABH, AFH, ANH, ATH Only
8661089 Shaft, Output AAH, ABH, AFH, ANH, ATH Only
8661020 Shaft, Final Drive Sun Gear AAH, ABH, AFH, ANH, ATH Only
SERVICE MANUAL REFERENCE:
This product change does not affect diagnosis, disassembly or assembly procedures for 1988 THM 440-T4 transaxles and is not shown in the 1988 THM 440-T4 Unit Repair Section of your service manual.
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TRANSAXLE APPLICATIONS: SUBJECT: ----------------------- ----------- 1988 THM 440-T4 (ME9) New Temperature Switch And New Wiring Harness Assembly
TRANSAXLE MODELS: VEHICLE APPLICATIONS: ----------------- --------------------- AAH, ABH, AFH, ANH, ATH C, E, K Cars
CHANGE TO ASSEMBLY COMPONENTS: (Figures 7, 8 and 9) ----------------------------------------------------- A new temperature switch, now located in the cooler line (Figure 8), and a new wiring harness assembly (48) for C, E, and K cars equipped with a 4.5L engine and THM 440-T4 transaxle. Transaxles using the new switch and wiring harness do not use a thermistor assembly (226), that was located on the pump assembly or the temperature switch assembly (426), that was located on the channel plate. A pipe plug (427, Figure 7) is now used on the channel plate in place of the temperature switch required for 1987 and prior model year transaxles.
SERVICE ACTION:
When servicing a 1988 AAH, ABH, AFH, ANH or ATH model THM 440-T4 transaxle, only use the new wiring harness assembly listed in the Service Parts Information section below. Also note in the wiring diagram (Figure 9) that PIN "E" of the electrical connector is not functional.
SERVICE PARTS INFORMATION:
Part Number Description Model Year - Model Usage ---------- ------------------ ------------------------------ 8668099 Harness Assembly, Wiring 1988 - AAH, ABH, AFG, ANH, ATH
SERVICE MANUAL REFERENCE:
This product change information is shown in the THM 440-T4 Automatic Transaxle Hydraulic Diagnosis section of your 1988 Service Manual. other product changes that are new for 1988 model THM 4440-T4 transaxles have been identified by an asterisk (*) in the Table of Contents.
----------------------------------------------------------------------------- TRANSAXLE APPLICATIONS: SUBJECT: ----------------------- ------------ 1988 THM 440-T4 (ME9) New Inside Detent Lever With New Manual Detent Spring and Roller Assembly
TRANSAXLE MODELS: VEHICLE APPLICATIONS: ----------------- ---------------------- CRH, CTH W Car
CHANGE TO ASSEMBLY COMPONENTS: (Figure 10) -------------------------------------------- A new inside detent lever (704) to be used with a new manual detent spring and roller assembly (707). The change to these components allows for smoother gear selection in "W" cars.
SERVICE ACTION:
When servicing a 1988 CRH or CTH model THM 440-T4 transaxle, only use the new parts as listed in the Service Parts Information section below. DO NOT use these components on other model THM 440-T4 transaxles or a misbuild will occur.
SERVICE PARTS INFORMATION:
Part Number Description Model Year - Model Usage ---------- ---------------- ------------------------ 8662925 Package, Manual Valve 1988 - CRH, CTH Models Lever and Link (W Car Only)
8662737 Spring and Roller 1988 - CRH, CTH Models Assembly Manual Detent (W Car Only)
SERVICE MANUAL REFERENCE:
This product change does not affect diagnosis, disassembly or assembly procedures for 1988 THM 440-T4 transaxles and is not shown in the 1988 THM 440-T4 Unit Repair Section of your service manual.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
