A/T - 700R4 New Piston Seal Design

SIL 89-36 (Nov)

SUBJECT: 1989 THM 700-R4/Hydra-matic 4L60

New Short Up Piston seal Design -- Forward, 3-4, Overrun and Reverse Input Clutches

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.




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. (See Figure 1)

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 obtain in two separate packages:

PART NUMBER 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