Abstract: A traversing mechanism for the mast of a side loader vehicle having a chassis including front and rear wheeled body parts interconnected by a backbone structure with a recess extending transversely of the vehicle between the body parts and having mast guide means along the sides of the recess, the traversing mechanism comprising mast supporting means moveable along the guide means, a prime mover operatively connected to a pair of idler rollers to translate them transversely of the vehicle, freely rotatable rollers journalled to the chassis at one side of the recess one at each end of the path of mast travel, a flexible member anchored at its ends to the chassis and passing in succession over one of the idler rollers, both freely rotatable rollers, and the other idler roller, the flexible member having a reach secured to the mast supporting means, whereby movement of the idler rollers by the prime mover will cause the flexible member to translate the mast supporting means along the guides.