The invention comprises mechanism for reducing hydraulic pressure on the engaged forward or reverse clutch when the decelerator pedal is fully depressed. The mechanism comprises an electric switch that is coupled to the decelerator pedal linkage for energizing a solenoid valve. The solenoid valve couples the modulation accumulator of the power shift tranmission to sump when the electric switch is closed. This decreases the hydraulic pressure on the engaged forward or reverse clutch so that it can slip if braking force is applied to the vehicle.
