The OEM steering gear in these trucks have always been a problem until now. PSC introduces the XD steering gear featuring a 45mm sector shaft and bearing to prevent the pitman arm and sector shaft to flex and cause the lower seal to fail. Larger teeth and other internal components have been increased in size to handle the loads when increasing tire size on your GM truck. This steering gear is also offered in a ported and balanced version for the SAS trucks that need the cylinder assist option. Offered only in a 4 spline sector shaft, if you have a 3 spline sector shaft you will need a new pitman arm.