A/T - New THM 440-T4 Information
88chevy08Number: 88-182-7A
Section: 7A
Date: MARCH, 1988
Subject: 1988 NEW PRODUCT INFORMATION THM 440-T4
Model and Year: 1988 CELEBRITY WITH THM 440-T4 TRANSAXLE
FIGURE 1 - THM 440-T4 TRANSAXLE IDENTIFICATION INFORMATION:
TO: ALL CHEVROLET DEALERS
This 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. Refer to each section of this bulletin for specific product change information.
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.
FIGURE 2 - MANUAL SHAFTS:
NEW MANUAL SHAFT
A new manual shaft (Figure 2, 702) that is 7 mm (.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.
When servicing the subject transaxle use the proper manual shaft listed below.
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.
FIGURE 3 - REVERSE REACTION DRUM:
NEW REVERSE REACTION DRUM
A new reverse reaction drum (Figure 3, 659) is used for all 1988 subject transaxles. The change to the reverse reaction drum is identified by a chamfer on both ends of the drum.
When servicing a 1987 or 1988 THM 440-T4 the new reverse reaction drum (659) may be used. When servicing a 1984 through 1986 THM 440-T4 you must use the previous reverse reaction drum.
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.
FIGURE 4 - 3RD CLUTCH PLATE (WAVED):
NEW 3RD CLUTCH WAVE PLATE
A new waved 3rd clutch plate (Figure 4, 640A) instead of a flat steel plate, is used in some 1988 applications. 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.
Transaxles models with waved 3rd clutch plate AAH, ABH, AFH, ANH, ATH, CFH, CMH, CRH, CTH, CWH, CXH. This new plate must not be used to service prior model year transaxles.
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.