NP203 Transfer Case Information
The New Process 203 is a chain-driven transfer case. This cast iron and aluminum transfer case is made up of four housings. This transfer case is a good, strong box except for the chain. This transfer case was used in full-size trucks and other production vehicles manufactured by GM, Dodge and Ford from1971 to 1979. It has five shift positions: High, Low, High Lock, Low Lock and Neutral. When using the Lock positions, the front and rear transfer case outputs will spin at the same speed. Some owners would also add a part-time kit which eliminates the differential so the NP203 works more like a traditional transfer case.
NP203 Transfer Case Identification
There were notable differences in the NP203 between the automakers that used it. If your New Process transfer case still has the identification tag above the front shaft output, you can use this to determine what model you have and its configuration. The information and photos below are how to identify your transfer case without a tag.
The Ford transfer case was normally a remote gearbox. The GM and Dodge used an adapter to mount the NP203 directly to the stock transmission. Since the front of these transfer cases look the same, identifying the differences between the Dodge and GM transfer cases without the stock adapter housing should be done by counting the transfer case input splines. The Chevy 203 transfer case versions include:
- A female 27-spline input originally coupled to a TH350 transmission
- A female 10 spline originally coupled to a SM465 transmission
- A female 32 spline originally coupled to a TH400 transmission
The adapters we offer for these transfer cases will normally require using your stock transfer case adapter. For assistance, contact Advance Adapters by calling us at 1-800-350-2223 or emailing sales@advanceadapters.com.
NP203 Originally Coupled to a TH350: This transfer case used in 1971-79 vehicles has a female 27-spline input.
NP203 Originally Coupled to an SM465: Used in vehicles 1971-79, this transfer case has a female 10-spline input.
NP203 Originally Coupled to a TH400: Found in vehicles 1973-77, this transfer case has a female 32-spline input.
NP 203 Transfer Case Specifications:
Case Material: Range Housing - cast iron; Chain Housing - cast iron; Differential Housing - aluminum; Output Shaft Housing - aluminum
Case Length 22-23 inches depending on the model
Shifting Type: Manual
High Range Ratio: 1:1
Low Range Ratio: 2.01:1
Input Splines: 10, 23, 27, 31 or 32
Transfer Case Weight: 200 lb.
Fluid Type: 10W-30 or SAE 30W motor oil