The governor spring is weak or missing.

Replace the governor.

The mechanical actuator is kinked, broken, or not properly adjusted.

Replace, adjust, or repair the cable.

The adjustment of the shift signal valve spring is too loose.

Tighten the spring adjusting ring to the specification.

The modulator valve is stuck open.

Check the spring adjustment.

The modulator valve is stuck open.

Replace the modulator. Refer to Transmission Modulator Valve Replacement .