A/T - Harsh Upshift/3-2 Shift Conditions: Overview
87olds6SUBJECT HARSH 3-2 SHIFT CONDITIONS - ALL
ALTITUDES - HARSH UPSHIFT CONDITIONS - ALL ALTITUDES ON-CAR SERVICE INFORMATION
1985-1987 CUTLASS CIERA, DELTA 88,
MODELS/YEARS NINETY-EIGHT, TORONADO MODELS
EQUIPPED WITH THM 440-T4 (ME9)
NUMBER: 87-T-50
DATE: October 16, 1987
SECTION: 7A
This bulletin supersedes Dealer Technical Bulletin 86-T-60 which should be discarded, and now applies to 1985 through 1987 models. Included is information on harsh shift conditions and on-car service for:
I. Harsh Part Throttle 3-2 Shift Conditions:
A. Very harsh part throttle 3-2 shift at 20-40 mph
B. Harsh 3-2 and/or 4-2 shifts
C. Intermittent harsh 3-2 shifts
II. Harsh 3-2 Shift - High Altitude Only
III. Harsh 3-2 Shift - Low Altitude Only
IV. Harsh 3-2 Shift Maneuver at 17-20 mph
V. Harsh 3-2 Coastdown Bump at 20-40 mph with 3.8L Engine
VI. Harsh Upshifts - High Altitude Only
IMPORTANT: Before performing any service action, make sure to diagnose the specific shift condition and altitude that affects vehicle performance. Do not assume that every condition listed applies to the vehicle.
Bulletin Covers:
Harsh shift conditions and the specific service information that applies to each of these conditions. However, some other items that affect transaxle operation which may also contribute to these harsh shift conditions are:
- Vacuum leaks (low vacuum supply to the vacuum modulator - 13-18 in. Hg. required.)
- Paint in the modulator tube restricting vacuum to the modulator causing a delayed response to throttle movement
- Sticking modulator valve
- Sticking 1-2 servo valve
- Mining checkballs (No. 2, No. 4, or No. 12)