A/T - New Clutch Piston Seal Design
89pontiac16Bulletin Number: 89-7-33
Reference Number: 977121
Publish Date: 6/89
Subject: NEW SHORT LIP PISTON SEAL DESIGN FORWARD, 3-4, OVERRUN AND REVERSE
Models INPUT CLUTCHES
Affected: 1989 FIREBIRD MODELS WITH 700-R4/4L60
BULLETIN COVERS: (Figure 1)
Figure 1:
New clutch piston seal design. The following clutch piston seals have been redesigned to include a shorter lip profile for ease of assembly:
Clutch Piston Outer Seal Clutch Piston Inner seal
* 3-4 * 3-4
* Forward Forward
* Overrun Overrun
* Reverse Input Reverse Input
Clutch pistons have not changed.
Figure 2 - THM 700-R4/HYDRA-MATIC 4L60 Transmission Identification Information:
DATE OF PRODUCTION CHANGE: (Figure 2)
Beginning February 28, 1989 (Julian Date 059), all 1989 Hydra-matic 4L60 transmissions have been built using seals with the new short lip design on pistons designated above with an asterisk. The remaining three seals (Forward, Overrun and Reverse Input inner seals) will change to the short lip design at a future date.
SERVICE PARTS INFORMATION:
Short lip seals are interchangeable with the current seals. The new design will replace the current seal in service packages as stock is depleted. All eight seals are available in the overhaul kit, or they may be obtained in two separate packages:
Part No. Package Contents
8642919 3-4 Clutch Piston Inner and Outer Seals
Forward Clutch Piston Inner and Outer Seals Overrun Clutch Piston Inner and Outer Seals
8657922 Reverse Input Clutch Piston Inner and Outer Seals
Parts are currently available from GMSPO.