NVG 263 Variations
WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The HD and the SHD model share many of the same components, but the increased torque capacity of the SHD requires a double row input bearing, larger diameter rear output shaft, rear output shaft bearing higher capacity, larger rear seal and case halves machined differently.
The NVG has some changes from prior model years. The NVG 263 has a new style encoder motor. The oil pump on the HD variations is now the same as the SHD variation. Along with the oil pump change, the oil pump suction pipe and screen were changed to the SHD style. The NVG 263 HD now uses a different rear output shaft.