IA. Very Harsh Part Throttle 3-2 Shift At 20-40 MPH --

Figure 2:

1985 - 1990 6000
1987-1990 Bonneville Models
1988-1990 Grand Prix Models

Service Procedure:

A part throttle downshift is a quick apply of the accelerator pedal beyond a medium throttle position (approximately 1/2 of accelerator pedal travel), forcing a downshift.

A harsh part throttle 3-2 shift at 20-40 mph may be caused by a missing or mislocated # 2 3-2 control checkball (Figure 2). Remove the valve body to inspect for proper checkball location or damage to the spacer plate. A mislocated checkball may have bent the spacer plate. Also inspect the # 12 1-2 servo feed checkball to ensure it is seating properly.