Vacuum Regulator Valve

The vacuum regulator valve provides vacuum signals to control automatic transmission shift points. Vacuum setting of valve should be checked and adjusted periodically, using the following procedure. Engine MUST NOT be running during this procedure.

Loosen vacuum regulator valve so it is free to rotate on pump. Attach a hand-held vacuum pump and apply 20 in. Hg. to bottom port of valve. Attach vacuum gauge to top port of valve.

NOTE: Valve must be set while rotating valve body in clockwise direction only.

Insert Gauging Block (J-33043) between gauge boss on injection pump and wide open stop screw on throttle lever (switch on position). See Fig 1.
Rotate and hold throttle shaft against gauging block. Slowly rotate vacuum regulator valve body clockwise (facing valve) until vacuum gauge reads 7.4-8.6 in. Hg. Hold valve body at this position and tighten mounting screws.
Check adjustment by allowing throttle shaft to return to idle stop position. Then rotate throttle shaft back against gauging block. Vacuum gauge reading must be within 7.4-8.6 in. Hg. If vacuum is outside limits, reset valve.

Fig 1: Vacuum Regulator Valve Adjustment