Tractor with front suspension

The control (18) includes a fluid system having a fluid passage (78,84) in connection with a rod end chamber (86) and a piston end chamber (80) of a fluid cylinder (50) connected to the front axle (16) and a front end (28) of a vehicle (10) and extendible in length for increasing a distance between the front axle (16) and the front end (28), a progressive control valve (60) is disposed in the (78,84) passage and is controllably movable through a range of progressively more restrictive partially open positions. The valve (60) can also have a one-way flow position to allow fluid flow only from the piston end chamber (80) to the rod end chamber (86), to allow only retraction of the cylinder (50). A controller (72) is automatically operable for causing the valve (60) to move through the range of progressively more restrictive partially open positions as the fluid cylinder (50) is increasingly extended, and for moving the valve (60) to the one-way flow position when the cylinder (50) reaches a predetermined length. Operation of the control (18) can be enabled by actuation of a drive for the front axle (16), such as mechanical front drive.