A/T - 440T4 Harsh 3-2 Detent Downshift
TRANSMISSION: 440-T4BULLETIN: # 086
SUBJECT: Harsh 3-2 downshift
APPLICATION: GM
DATE: December 1991
A harsh 3-2 detent downshift may be caused by the 3-2 control valve spring calibration and/or a missing or undersize feed hole in the spacer plate.
Enlarge the hole shown on the spacer plate to .045". (Figure 1) Some spacer plates may be missing this hole. If the hole is missing, lay a gasket on the plate to identify the hole location, and drill a .045" hole.
Remove the 3-2 control valve (Figure 2) spring and 3-2 control valve.
Place the spring over the stem of the valve, and press down on a scale until the tip of the stem just touches the scale. (Figure 3). The scale should read 5-1/2 - 5-3/4 lbs. Trim the spring as necessary until the desired weight is obtained.
BULLETIN RECAP
^ Check the spacer plate for missing or undersized hole
^ If necessary, modify the 3-2 control spring
FOR ADDITIONAL INFORMATION: 1990 Seminar Book