A/T - THM 440-T4 Soft/Slipping/No 1-2 Upshift
87cad6Bulletin No T 88-7
File in Group 7
Number 169
Corp. Ref. No. 677132
Date Sept. '87
SUBJECT: SOFT, SLIPPING OR NO 1-2 UPSHIFT - THM 440-T4
MODELS AFFECTED: 1985 DE VILLE AND FLEETWOOD 1986 ELDORADO AND SEVILLE
Some 1985 De Ville and Fleetwood, and 1986 Eldorado and Sevilles equipped with THM 440-T4 transaxle may experience a soft, slipping or no 1-2 upshift condition.
This condition may be the result of the two cast iron seals between the driven sprocket support and the second clutch housing binding to the driven sprocket support and wearing or grooving the second clutch housing hub.
At the start of production 1987, these cast iron rings were replaced by Vespel (plastic) rings and four lobe seals. This change also took place on all Service Replacement Transaxle Assemblies (SRTA) models effective December 31, 1986 (Julian Date 365).
FIGURE 1 - CHECKING FOR WEAR:
To repair this condition, inspect the second clutch housing (see Figure 1) for wear (grooves) and inspect the cast iron oil seal rings for wear (indicated by shiny surface). The driven sprocket support may not appear affected but will require replacement. Due to 1987 changes to the driven sprocket support, the new Vespel oil seal rings and four lobe ring seals are not interchangeable with the cast iron oil seal rings on models built prior to 1987 start of production (SOP).
FIGURE 2 - NEW DESIGN DRIVEN SPROCKET SUPPORT:
Changes to the driven sprocket support include; deeper seal ring grooves and cutouts to accommodate the tangs (refer to Figure 2) which prevent the Vespel oil seal rings from rotating.
The new Vespel oil seal rings, four lobe ring seals and driven sprocket support are included in the following service package, which services all model years.
Model Years Part Number Description
1985-1987 8662523 Assembly, Driven Sprocket Support Complete
NOTE: This new support can be used with either the five or six plate second clutch pack.
IMPORTANT: When installing a four lobe ring seal, make sure it is not rolled or twisted. Lubricate the Vespel rings with transmission fluid or petroleum jelly for easier installation into the second clutch housing.
For warranty purposes, use Labor Operation number: K7530
C Car 5.5 Hours
E/K Car 6.1 Hours