The NV 4500 is a 5 speed manual transmission with the fifth speed an overdrive ratio. The 5 forward gears and the reverse gear are fully synchronized. The shifting components are located in the shift cover. The shift cover is not rebuildable.

The 5th speed gear is located on the countershaft in the extension housing. There are 2 types of extension housings depending on the vehicle model.

The main shaft varies between models due to the extension housing configurations.