Abstract: A tank filling drop tube assembly (2, 48) includes a drop tube (16, 50) and a linear motion shut-off valve assembly (24). One embodiment includes a barrier (30) which seals the interior of the drop tube. Outlet ports (32) are formed through the drop tube above the barrier. A restrictor sleeve (26, 58) is mounted around the outside of the drop tube just below the outlet ports. The restrictor sleeve is connected to a float (36) at the upper end (10) of the drop tube. When the tank (4) is substantially filled, the float lifts the restrictor sleeve to seal the outlet ports to help prevent overfilling of the tank.