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NP203 New Process Transfer Case Diagram


Index Number Part Description
1 Adapter
2 Input Drive Gear Pilot Bearings
3 Range Selector Sliding Clutch
4 Range Selector Housing
5 Low speed Gear Bushing
6 Lowe Speed Gear
7 Thrust Washer & Locating Pin
8 Gasket
9 Input Bearing
10 Input Bearing
11 Input Bearing Retaining Ring
12 Input Bearing Retaining Ring
13 Thrust Washer
14 Intermediate Housing
15 Drive Shaft Sprocket
16 Gasket
17 Sliding Lock Clutch
18 Differential Housing
19 Rear Output Front Bearing
20 O Ring
21 Vent
22 Oil Seal
23 Oil Seal Vent
24 Oil Pump
25 Speedometer Drive Gear
26 Rear Output Rear Bearing
27 Rear Output Shaft Housing
28 Rear Output Shaft
29 Rear Output Washer
30 Rear Output Nut
31 Rear Output Rubber Washer
32 Rear Output Yoke
33 Rear Output Bearing Oil Seal
34 Shim Pack
35 Input Shaft O Ring Seal
36 Input Shaft Roller Bearings
37 Differential Carrier Assembly
38 Spring Cup Washer
39 Lockout Clutch Spring
40 Drive Shaft Sprocket Rear Retaining Ring
41 Drive Shaft Sprocket Front Retaining Ring
42 Front Output Rear Bearing Cover
43 Front Output Rear Bearing
44 Front Output Drive Sprocket
45 Front Output Rear Bearing Cover Gasket
46 Magnet
47 Drive Chain
48 Front Output Bearing Retainer Gasket
49 Front Output Bearing Outer Retaining Ring
50 Front Output Bearing
51 Front Output Shaft Seal
52 Front Output Bearing Retainer
53 Rubber Spline Seal
54 Front Output Washer
55 Front Output Nut
56 Front Output Yoke
57 Countergear
58 Countergear Spacers & Bearings
59 Counter Gear Shaft
60 Countergear Thrust Washer
61 Adapter to Selector Housing Gasket
62 Input Bearing Retainer Gasket
63 Input Bearing Outer Ring
64 Input Gear Bearing
65 Input Gear Seals
66 Input Bearing Retaining Ring
67 Input Gear
68 Input Gear Bearing Retainer

The New Process 203 was used in GM, Ford, and Dodge through the 70's behind auto and manual transmissions. They were originally a full time 4wd 'case, meaning all 4 tires receive power at all times. This was made possible through use of a differential in the back of the 203 that let the front and rear drive shafts turn at different speeds as just as a diff in an axle lets each axle shaft turn at a different speed. For off road use, the 203 had a "lock" position in which the differential was locked making the front and rear outputs spin at the same speed. Shift positions are: High, Lo, High Lock, Low Lock and Neutral.

A popular modification to the 203 was to install a "part time" kit to eliminate the differential. In this configuration the 203 operates like more conventional transfer cases in that it's either in 2wd or 4wd and when in 4wd the power is evenly split from front to rear.

The NP203 is identified by several features.

  • The transfer case is made up of 4 sections bolted together, a range box, the chain case which houses the chain drive to the front driveshaft output, the differential housing, and the output housing. The front 2 sections are cast iron, the back 2 sections are typically aluminum.

  • The overall length is about 22-23" from the face of the case to the rear output yoke centerline.

  • The shifter is a somewhat complicated box that actuates the 2 levers on a single shaft on the side of the range box section of the 203.

  • The model tag (if it still exists) will be found on the front of the chain case above the front output shaft. It will list the model number, the manufacture date and the gear ratio.

Exploded View Diagrams of the NP203 Transfercase  (click to enlarge)


NP203 Resources:

NP203 + NP205 Transfercases
Np203+np205 transfer cases by Gordon Pritchard and bc4x4.com. 
How to Fix Up the NP203 Transfer Case
Pertersons 4Wheel & Off-Road details how to rebuild the full-time four-wheel-drive NP203 transfer case.

Transfer Cases Doubler NP203 / NP205 Adaptor
The NorthWest FabWorks Adaptor kit allows you to mate the reduction box portion of a NP203 transfer case to the stout NP205.

NP203 Transfer Case Data Sheet

NP203 based "Doubler” systems
Example of a "Doubler" system: NP203 reduction unit mated to an NP205

New Process 203 Transfer Case Tech




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