Abstract: An elevation apparatus for lifting a truck box pivotally mounted on the truck chassis comprises a first main cylinder piston arrangement arranged at the front end of the truck box and a second subsidiary piston/cylinder arrangement provided adjacent the midpoint of the truck box. The secondary piston/cylinder arrangement includes two cylinders, one on either side of the chassis and arranged in the lowered position to lie substantially along the chassis with the piston directly coupled to the truck box and the cylinder coupled directly to the chassis. A latch mechanism for the piston of the main cylinder acts to lock the piston head in position on the chassis when the truck box is lowered and to release the piston head when the truck box is raised so that the piston head moves free from the latch mechanism when the secondary cylinders raise the truck box beyond the extent of the first piston.