A chassis-height adjustment system for selectively raising and lowering a chassis relative to a ground surface includes a plurality of support assemblies supporting a chassis on respective ground-engaging elements. Each support assembly has a height adjustment actuator. Each height position sensor senses an adjustment position one of the height adjustment actuators and generates a height signal. Each of the support assemblies may be mounted to the chassis by a track-width adjustment mechanism having a track-width adjustment actuator. The height adjustment system is controlled in a manner to synchronize each height adjustment actuator with the other actuators. Adjustment of one or more height adjustment actuators is slowed or stopped in the event that other actuators need to catch up. The track-width adjustment actuators may shift the position of the associated ground-engaging element laterally relative to the chassis to keep the ground-engaging elements from sliding laterally as the chassis height changes.