An adjustable shelving assembly for a refrigerator appliance includes a braking rack fixed on a rear wall of a cabinet and a drive screw extending substantially parallel to the braking rack. A shelf is fixed to a clutch assembly that includes a half nut positioned around the drive screw and a brake pawl positioned adjacent the braking rack. An actuation mechanism is operably coupled to the half nut and the brake pawl for moving the clutch assembly between a first position where the half nut closes to engage the drive screw and the brake pawl is disengaged, and a second position where the half nut is open and the brake pawl engages the braking rack.