Lumina L4-151 2.5L (1991)
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.
HYDRA-MATIC 4T60 Transaxle Identification Information
IB. Harsh 3-2 and/or 4-2 Shifts
