A vehicle traction system includes a first traction wheel forming part of a first propulsion system including a mechanical drive train, a second traction wheel forming part of a second propulsion system including a hydraulic pump for powering a hydraulic motor, one sensor indicating a take-off condition, and a control unit for controlling the second propulsion unit. The control unit is programmed to automatically detect a take-off condition by the sensor and send an input to the control unit that a take-off condition is fulfilled, automatically provide a traction force from the second propulsion system in response to the indication that there is a take-off condition of the vehicle present and an indication that a traction is or will be provided by the first traction system, and automatically control the second propulsion unit by the control unit in dependence of the manually controlled torque from the first propulsion unit.