A method and apparatus for controlling frame rise on a heavy duty truck
having a frame, a drive axle connected to the frame, and a selectively
lockable suspension component disposed therebetween for maintaining the
relative position therebetween. Signals indicative of at least one of the
following vehicle operating parameters: engine speed, brake pressure,
vehicle speed, air bag pressure, steering wheel angle, vehicle height, or
throttle position are monitored and a predicted thrust is calculated that
will be applied to the drive axle based on the monitored signals. The
selectively lockable suspension component is locked if the predicted
thrust exceeds a predetermined threshold and is also controlled with
respect to other operating parameters such as whether vehicle brakes are
applied, any instantaneous change in torque, vehicle operating speed, and
the length of time the selectively lockable suspension component has been
locked.