NEW ROCKER-JOINT DRIVE LINK & DRIVE/DRIVEN SPROCKET ASSY.

SUBJECT: NEW ROCKER-JOINT DRIVE LINK AND DRIVE/DRIVEN SPROCKET ASSEMBLY - INFORMATION

MODEL/YEARS: 1993 VEHICLES WITH 4T60 OR 4T60-E TRANSAXLES

SERVICE INFORMATION: (Figure 1) ------------------- A new Rocker-Joint Design Drive Link Assembly (510/507) has been released for all 1993 HYDRA- MATIC 4T60 (RPO ME9) and select 1993 HYDRA-MATIC 4T60-E (RPO M13) transaxles.

Due to the unique Rocker-Joint drive link configuration, it was necessary to change the tooth geometry on the drive and driven sprockets.

Note: A Rocker-Joint drive link assembly cannot be used on a transaxle that previously had a Round Pin drive link unless the drive and driven sprockets have been updated (or vice versa).

Note: If a Rocker-Joint link is assembled on a unit without updating the drive and driven sprocket (or vice versa), wear on the sprockets and drive link will be greatly increased. Also, drive link noise may also increase to the level that may be considered unacceptable.

Rocker-Joint Advantages Over Round Pin Drive Link Design

o Low friction of design permits smoother operation at high speeds.

o Reduced chain wear.

o Higher efficiency at continuous speeds.

DATE OF PRODUCTION CHANGE:

The new Rocker-Joint design was implemented into production on December 21, 1992 (Julian Date 356).

Drive/Driven Sprocket Implementation Date 37/33 Sprocket Ratio - December 21, 1992 33/37 Sprocket Ratio - December 21, 1992 35/35 Sprocket Ratio - may be implemented mid-year 1994

TRANSAXLE MODELS:

3AVW 3AWW 3AZW 3AMW 3ANW 3APW 3ABW 3BTW 3CXW 3CZW 3PHW 3CWW 3WFH

IDENTIFICATION OF PARTS: (Figures 1 & 2) ----------------------- Identification of new parts:

P/N Description Identification --- ----------- -------------- 8682597 Spkt/Sleeve Asm. - Drive 37T Part Number will be in MAGENTA ink. 8682600 Sprocket-Driven 33 Tooth Part Number will be in MAGENTA ink. 8682602 Sprocket-Driven 37 Tooth Part Number will be in MAGENTA ink. 8682599 Spkt/Sleeve Asm.-Drive 33 Tooth Part Number will be in MAGENTA ink. 8682603 Link Asm.-Drive Master link will be COPPER in color.

Note: Magenta is a moderate to vivid purplish red or dark to strong reddish purple.

PART INFORMATION:

Existing New Models Round Pin Rocker Joint Description Affected --------- ------------ ----------- -------- 8644679 8682597 Spkt/Sleeve Asm. Drive, 37 Tooth 3AVW,3AWW,3AZW,3AMW, 3APW,3ABW,3BTW,3CXW, 3CZW,3PHW,3WFH

8651568 8682599 Spkt/Sleeve Asm. Drive, 33 Tooth 3CWW

8675035 8682600 Sprocket-Driven 33 Tooth 3AVW,3AWW,3AZW,3AMW, 3ANW,3APW,3ABW,3BTW, 3CXW,3CZW,3PHW,3WFH

8678146 8682602 Sprocket-Driven 37 Tooth 3CWW

8660099 8682603 Link Asm.-Drive 3AVW,3AWW,3AZW,3AMW, 3ANW,3APW,3ABW,3BTW, 3CXW,3CZW,3PHW,3WFH, 3CWW

Parts are expected to be available on July 26, 1993.

SERVICE MANUAL INFORMATION:

Refer to the appropriate service manual section, Automatic Transaxle On-Vehicle Section 7A for proper on vehicle service to remove and replace a 4T60/4T60-E transaxle. Refer to Automatic Transaxle Unit Repair Section for proper disassemble and assemble procedures.

WARRANTY INFORMATION:

Labor time should be charged under Operation Number K-7520 for "Link Assembly, Transaxle Drive - Replace":

Including: Cooler line flush, oil pressure test, clean and inspect parts and all necessary measurements and adjustments.

Note: For check and adjust toe-in, refer to operation E2000 and add the applicable times to the regular hours column. Applies to W series only.

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.