An adjustment mechanism is disclosed for moving a movable member relative to a fixed member. A threaded screw is fixedly secured to the fixed member. A gear is rotatably disposed about the threaded screw. A housing includes a bore and an opening in a lower surface. A rotatably driven worm is disposed within the bore and includes a threaded outer surface that protrudes through the opening in the lower surface of the housing and threadably engages the gear. A generally U-shaped retainer strap partially surrounds the gear and is adapted to couple the housing and gear together to align and preload the worm and gear. A generally U-shaped bracket is adapted to be fixedly secured to the movable member, wherein the gear, housing, worm, and retainer strap are disposed within the bracket and the threaded screw passes through a pair of openings in the bracket.