Dodge has used three Input Shafts in New Process NV273D Transfer Cases. A 23 spline input shaft is used in most behind automatic transmissions. Trucks with manual transmissions and heavy-duty automatics like the Aisin 6 speed have one of two 29 spline input shafts.
The non-rebuildable Planetary Assembly has 6 needle bearing supported pinion gears that are driven by the input shaft to provide low range gearing for the NV273D Transfer Case. In most cases, the Planetary Assembly will never need replacement, but the 34 small needle bearings under each pinion gear and the pinion gear teeth themselves are prone to damage from from lack of lubrication/dirty oil and from metal chips that may occur under high wear situations. The two Planetary Thrust Washers and the Snap Ring should be replaced any time you perform major transfer case service. The Planetary Annulus Gear, which is the big gear pressed in the front case into which the Planetary Assembly fits, is only sold as part of the Front Case Half.
