A/T - New I.D. Codes & New Overhaul Packages
89buick11Bulletin: 89-7440-10
Date: July, 89
Ref. No.: 89-176-7440
Corp. Ref. No.: 977123
Figure 3 - Service Information For New Models:
SUBJECT: NEW TRANSAXLE I.D. CODES
MODELS AFFECTED: 1989-90 MODELS WITH 440-T4/4T60 TRANSMISSIONS
BULLETIN COVERS
A change of the 3rd clutch plate fiber (640) material requires that all 1989 and 1990 transaxles models built after Julian Date (076) March 17, 1989, have new calibrations and new two letter (alpha) model codes. A new overhaul package and 3rd clutch plate assembly package will service the new 1989 and 1990 models.
Models built after Julian date (076) March 17, 1989, have the new model codes and contain a new spacer plate (031) (most models), 3-2 control spring (341), 2-3 accumulator spring (336), 1-2 servo cushion spring (559) (all models except AA, AB and AF) and the new 3rd clutch plate assembly 640). The updated valve body assembly will have an update level laser etched into the casting by the servo pipes (note service information for valve body I.D. and new spacer plate information - figure 3).
Figure 1 - HYDRA-MATIC 4T60 Transaxle Identification Information:
SERVICE PROCEDURE
When replacing the 3rd clutch fiber plates (640) on 1989 or 1990 models for any reason, check the two letter model code on the tag as shown in Figure 1.
Figure 2 - Old and New Model Alpha Codes For New Calibrations:
IMPORTANT: Order Overhaul packages, 3rd clutch plate assembly packages and valve body assemblies by the model code for all early 1989 models, and the new 1989 and 1990 models. Reference chart, Figure 2.
Figure 4 - Marking For New 3rd Clutch Plate Assembly:
When servicing a Hydra-matic 4t60 transaxle you may notice: the new 3rd clutch plates may have the following markings as shown in figure 4. The new 3rd clutch plates may have four black stripes about an 1/8" wide and the notch may not be in one of the teeth. Some early build models after Julian Date (076) will have some of the markings or none at all.
IMPORTANT: THE FOLLOWING CONDITIONS COULD OCCUR IF PARTS ARE MIXED.
1. Harsh shifts or potentially a tie-up condition (worse in altitudes) on 2-3 and 3-2 shifts if the old 3rd clutch plates are installed into a transaxle built after the Julian Date (076) (with new model codes).
2. A slip-bump condition on 2-3 and 3-2 shifts if the new 3rd clutch plates are installed into a transaxle built before Julian Date (076) (old model codes).
Figure 2 - Old and New Model Alpha Codes For New Calibrations:
SERVICE PARTS INFORMATION
Part Number Description Model Year - Model Usage
8662990 3rd Clutch Plate 1989/1990 - See New Models
Assembly Package Listed in Figure 2
8662989 Overhaul Package 1989/1990 - See New Models
Listed in Figure 2
Parts are expected to be available (for part numbers 8662990 and 8662989) on 07-17-89. 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.
When the supply of old style 3rd clutch plate assemblies (both 3rd clutch plates and overhauls) is depleted the new style 3rd clutch plates and an instruction sheet will be available. The instruction sheet will show which calibration update kit to order for each model built after Julian Date (076).
SERVICE MANUAL REFERENCE
Refer to the appropriate 1989 Service Information Manual.