A/T - Harsh Upshifts at High Altitudes
Number 86-7-36 Date 9/86Subject: HARSH UPSHIFTS AT HIGH ALTITUDES
1985-86 6000 MODELS WITH THM 440-T4 TRANSAXLE (CW, CP, HT, CM, CN, HJ, HA, CFH, CMH, CNH, HJH, HBH)
THM 440-T4 TRANSAXLE I.D. NAMEPLATE WARREN, MICHIGAN:
Some 1985-86 6000 models equipped with a 2.8L engine and a THM 440-T4 transaxle may exhibit harsh upshifts when operated at high altitudes. This condition may be caused by excessive line pressure resulting from insufficient engine vacuum. Refer to Figure 1 for transaxle identification information.
A new vacuum modulator assembly and modulator valve* have been released for service in a package (Part Number 8646956) for the harsh upshifts condition. The package consists of:
-- Transaxle Vacuum Modulator Assembly
-- Modulator Valve
-- O-Ring Seal
-- Instruction Sheet
*Note: A new engine vacuum line (Part Number 14062624) must be
installed with the service package.
CORRECT MODULATOR VALVE ORIENTATION:
Refer to the appropriate Service Manual for removal and installation procedures as well as to Figure 2 for correct modulator valve orientation.
The service package ONLY applies to the following THM 440-T4 models:
1985 Models 1985-1/2 Models 1986 Models
CW CM CFH
CP CN CMH
HT HJ CNH
HA HJH
HBH