Viii. Harsh Upshifts At High Altitude* Only

1985-1986 DeVilles and Fleetwoods and 1986 Eldorados and Sevilles





* - Refer to Figure 8 for designated high altitude counties.

Service Procedure:

Harsh upshifts for ALL GEARS at high altitudes may be caused by high line pressure due to low engine vacuum. This condition may be corrected on certain transaxle models by installing the appropriate aneroid modulator Service Package.





Based on vehicle applications each package contains:

(1) Vacuum Modulator Assembly
(1) Modulator Valve
(1) O-Ring Seal
(1) Spacer Plate
(5) Gaskets
(1) Cup Plug (Orificed)
(2) Instruction Sheets

Parts are currently available from GMSPO.

A new vacuum fine from the engine to the vacuum modulator MUST also be installed when using the service packages listed previously

P/N Vehicle Application

1643771 DeVilles and Fleetwoods
1641441 Eldorados and Sevilles

Parts are currently available from GMSPO.

Please refer to appropriate Labor Operations for applicable years.