New Process NP205

NP205 Transfer Case Specs & information

The NP205 is arguably the King of Transfer Cases. It's a heavy duty, gear driven unit that was used in a variety of applications, including Ford, Dodge, and GMC/Chevrolet heavy duty pickups. It is smaller, stronger, and more robust than the chain driven NP203, and its ruggedness on the trail is largely unsurpassed for an OEM transfer case. 1.96 : 1 low range is not particularly desirable, but the aftermarket offers upgrades that can lower the factory ratio by as low as 3.00 : 1. Twin sticking is also an option, either through aftermarket components or the DIY version, which requires disassembly and modification of the shift rails.

The Dodge and GM versions had identical bolt patterns - and 8 bolt pattern for 1971 - 1985 units, and a 6 bolt pattern for later cases. GM models used a 27 spline input when mated to the TH350, and a 32 spline input behind the SM465 manual transmission. Dodge cases were typically 23 spline male input, which required a special sleeve to connect the transmission output shaft to the transfer case input shaft. In diesel applications, the Dodge NP205 had a 29 spline input, which is exclusive to the GETRAG 5 speed manual transmission. Ford used an NP205 with a 6 bolt pattern. They also commonly used a divorced case, which used 1310 series input and front output yokes, and a 1330 series rear output yoke.

It is common to see NP203/NP205 "doublers", which is quite literally a NP203 mated to a NP205. More specifically, the process mounts the range box (not the entire transfer case) of a NP203 to the input side of a NP205, using machined adapters to mate the parts securely. This accomplishes many things - first and foremost, it allows for up to a 3.94 to 1 reduction (2.01 for the NP203 x 1.96 for the NP205, often advertised as a nominal 4:1) with low range engaged in both transfer cases, effectively doubling the gear reduction of a standard NP205 transfer case. Furthermore, it eliminates the potentially problematic and less favorable chain drive system of the NP203. Doubling the two cases require only using the NP203's helical geared reduction box, NOT the entire drive system. Doubling the two cases is an affordable technique in order to retain an extremely stout gear train while reaping the benefits of a compound low range setup.


NP205 Specs


New Process Gear


Part time, gear driven, helical cut gears


• 1967 - 1991 GMC/Chevrolet fullsize
• 1973 - 1979 Ford fullsize
• 1969 - 1993 Dodge fullsize
• 1965 - 1975 International pickups

Case Material:

Cast iron, one piece

Shift Type:



GM NP205s were married, Ford, Dodge, and IH offered divorced versions


High Range:

1.00 : 1

Low Range:

1.96 : 1

Input Splines:

10 (common w/ manual trans), 23 (Dodge), 27 (TH350), 29 (Dodge diesel), 31 (Ford), 32 (TH400, SM465)

Output Splines:


Pass/Driver Drop:

GM/Dodge are passenger side drop, Fords are driver side drop


~ 140 lbs dry


~ 13" long (16" for IH), 18" wide, and 12" tall.

Fluid Type:

80w-90 gear oil


ID Tag mounted on transfer case above the front output shaft will list model, serial number, and ratio.


New Process NP205 exploded view