A/T - Intermittent Slip In Forward/Reverse When Cold
88pontiac24Bulletin Number: 89-7-8
Reference Number: 877150
Publish Date: 11/88
Subject: INTERMITTENT SLIP IN FORWARD AND/OR REVERSE WHEN COLD
Models
1989 6000, BONNEVILLE AND GRAND PRIX
Affected: EQUIPPED WITH THM 440-T4/HMD 4T60
FIGURE 1 - THM 440-T4/THM F-7 TRANSAXLE IDENTIFICATION INFORMATION:
BULLETIN COVERS:
An intermittent slip in forward and/or reverse when the transaxle is cold may be caused by leaking Input Shaft Oil Seal Ring(s) (624). This may be due to one or more undersized Input Shaft Oil Seal Ring(s) that seal the Input Clutch and 3rd Clutch feed holes. The transaxle may slip less in Reverse or Manual Lo (D1) ranges (due to boosted line pressure) than in Overdrive (D4), Drive (D3), or Manual Second (D2).
FIGURE 2 - INPUT SHAFT OIL SEAL RINGS:
SERVICE ACTION: (Figure 2)
Disassemble the transaxle, remove the Shaft and Housing Assembly (626) and inspect the Input Shaft Oil Seal Rings (624) while in the grooves. The rings should take up most of the groove width. If the ring (s) only takes up about half of the groove width then replace them with rings from the package listed under Service Parts Information. Follow procedures outlined in the 1989 Service Manual Unit Repair Section.
Important: Inspect for burned Input and 3rd Clutch Plate Assemblies. Replace if necessary.
SERVICE PARTS INFORMATION:
Part Number Description
8662959 Package, Overhaul Seals and Gaskets
(OK Input and 3rd Clutch Plate Assemblies)
8662960 Package, Overhaul Repair Complete
(For burned Input and 3rd Clutch Plate Assemblies)
Parts are currently available from GMSPO.
SERVICE NOTES:
The Oil Seal Rings may be different colors. This is just a way to tell the difference between suppliers that make the same ring.