The Novak Guide to the
New Process / New Venture Gear Transfer Case Input Gears
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New Process, chain-driven transfer case input gears really warrant their very own topic. There were some forty different variations of them made by NVG.
We've decoded most of the Jeep input gears and many are available for sale. The Jeep 231 transfer case is the main focus of our information here, but these gears interchanges can apply to:
- NP231
- NP233
- NP241 (Chevy, Dodge, Jeep JK)
- NP242
- NP243
- NP246
- NP247 (always has 23 splines)
- NP249 (always has 23 splines)
Gears that are not in the same family include:
- NP203 (gear driven)
- NP205 (gear driven)
- NP207 (spur cut gear)
- NP208, 218, 219, 229
- NP241OR (always has a short, 23 spline input gear)
Input Gears and Compatibility
Hold on to your seat...
The important variations to look for in the 231 transfer case are in the input gear. The 231 comes in 21 spline and 23 spline versions with long, medium (rare) and short variations.
The long shafts protrude 2.1" from the front mounting face of the transfer case. The short version protrudes 1.2". The rare medium shaft protrudes 1.7". You should be careful when swapping any of these gears due to different bearing widths and gear teeth. The following chart shows how to determine which input gear you might have by transmission. It is always recommended to verify first hand if possible.
| 21 Spline | 23 Spline | |
| Short Input | AW4 (through 1990) AX4 AX5 Peugeot BA 10/5 (earlier) |
Earlier
(pre-'95) AX15 30RH 32RH |
| Long Input | Later
(post-'94) AX15 TF904 TF999 Peugeot BA 10/5(later) NV3550 NSG370 |
|
| Medium Input | 46RE Jeep
ZJ's '93 to '95 only AW4 (post-'90) |
Because of differences in the cut of the gear, as a general rule, one should not interchange 1987-1993 gears with 1994-present gears. These years are not always hard and fast delineations. If one is not absolutely certain, disassembly and inspection is required.
Note that some transmissions change spline count. The Peugeot BA10/5 had both 21 or 23 splines. The AW4 had 21 splines through 1990. In 1991 (the same year the 4.0 HO was introduced) the AW4 splines increased to 23.
Anatomy of a New Process Input Gear
Available 23 Spline Gears
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Short length, wide bearing, early gear cut |
Medium length, wide bearing, early gear cut |
Long length, wide bearing, early gear cut |
Short length, narrow bearing, late gear cut |
Long length, narrow bearing, late gear cut |
Available 21 Spline Gears
|
Short length, wide bearing, early gear cut |
Short length, narrow bearing, late gear cut |
Click on any item description in blue below to expand its details for purchase. You can use your browser's Back button to return to this page and your cart items will remain. Long Style Input GearsMedium Style Input Gears Short Style Input Gears |
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Torqueflite 42RE Caveat
Unlike all other known transmissions to the Jeep New Process transfer cases, the Torqueflite 42RE transmission as found in 1994 ZJ Grand Cherokees features a unique output shaft with a pilot tip on the end of it. This shaft pilots into the NP input gear in a front-facing caged needle bearing. Note the image below.
| We once spoke with an Engineer at NVG. We questioned him as to why there were so many (forty-something) input gear variations in this popular series of planetary-reduction transfer cases. We told him that it was making our lives harder than we'd like. He responded, "Yeah. Isn't it ridiculous?" He went on to mention that he was part of a company committee whose goal it was to cut the number of gears available down to about seventeen versions, instead. |