Adapting the

New Process 435 Transmission

to the

Jeep Model 300 & FSJ New Process Transfer Cases

Adapter kit for NP435 to Jeep transfer cases

Kit 433-R, adapting NP435 transmissions to Jeep Dana Spicer Model 300 and FSJ New Process transfer cases

Kit contains:

  • Adapter housing
  • Transmission mainshaft, 23 spline output
  • Transfer case to adapter gasket
  • Transmission to adapter gasket
  • Fastening hardware
  • Modular steel mounting base
  • Instructions

Our NP435 to Dana 300 conversion makes for a strong, refined, compact geartrain assembly both on-road and off-road. It is one of the most persistently popular manual shift transmission conversions into Jeeps, providing a very compact geartrain, an excellent crawling gear, compatibility with several engines and simple installation.

np435_2wd_gasket np435_4wd_gasket

The Novak NP435 to Jeep transfer cases adapter is compact at only 3.2" long for a combined transmission and adapter length of 13.9". The adapter itself is cast and machined of 356-T6 aluminum heat treated alloy, featuring thick flanges, a heavy cross-section, and strength-adding gussets, and is drilled for multiple clocking locations from near-factory (20 degrees down) to near-flat (3 degrees down).

This transfer case adapter's design features a modular mounting and support system and mounting base, ready to accept our industry standard urethane isolator mount, available in Related Products, below.

The new Novak manufactured 23 spline output shaft is machined from premium alloy steel and hardened for maximum strength and longevity ready to be installed in your Borg-Warner transmission and then spline directly into the D300.

Applications & Compatibility

Compatible Transmissions


All Ford versions and most Dodge versions of the NP435 can be adapted to these transfer cases. GM NP435's and Dodge NP435's (early) are not compatible due to their input shaft ball bearing and snap ring mainshaft design. There are no inherent advantages to the 2wd vs. 4wd transmission. Note that divorced 4wd applications of the NP435 often (but not always) used a 2wd style tail housing and yoke. More details concerning these NP435's can be found here.

Mainshaft replacement is largely straightforward. Good work is within easy reach of the careful home mechanic and instructions are included. We also recommend our basic gasket & seal kit, or this is a good time for a more thorough master rebuild and update of the transmission.

Compatible Transfer Cases

All Jeep Dana 300 (and FSJ New Process) transfer case input shafts / gears feature 23 splines. Our included Mainshaft will spline in directly to these input shafts with no transfer case modifications required.


Because of parts availability and comparative reliability issues, We've been known to recommend replacing the older style FSJ New Process transfer cases (like the 219, 228 and 229) with a newer, more modern version such as the part-time 231J with HD SYE kit installed and upgrades as appropriate.

However, if you like your transfer case is in good condition, then move forward with the conversion.

Compatible Jeeps


This kit is compatible with most Jeeps that originally featured the D300 transfer case. If you are retrofitting both, keep in mind length and shifter location to ensure clearance for both. With a properly set-up short tail D300, this is as short as it gets for a 4 speed into a Jeep.

Compatible Engines

Any engine that can be made to work with the NP435 will work with this conversion. They include:

Ford and AMC engines are the two most natural and recommended choices for this transmission.

Related Products

Urethane Rear Mount for Crossmember
Dana 300 Rebuild Kit
Billet aluminum Dana transfer case pan
Dana 300 billet rear bearing cap
Dana 300 twin stick shifter
1976-1986 Jeep floor tunnel cover
435 Shifter
Shifter Retention Kit, SM420, SM465, T176, NP435
Billet PTO Cover
Dana 300 Super Short Tailhousing
Ford Engine Mounts for Jeeps

Installation Requirements


The transmission shaft installation takes more specialized tools, heavy snap ring pliers, a press to remove and replace bearings, etc. Normal mechanics tools are required for the balance of the installation.

Engines & Engine Mounting

Engine placement in these Jeeps should consider the following points:

  • Left-right offset location is similar to factory at ~1-1/4" to the driver's side
  • Avoid installing the engine too low (axle clearance and other issues)
  • Avoid installing the engine too high (transmission tunnel interference, etc.)
  • Set your engine to 4-7 degrees of tilt rearwards, like the factory engine & powertrain
  • It is usually best that Chevy and Gen III+ V8 engines install approximately 3" further forward, using the back of the engine block face as the datum
  • When mocking up your engine installation location, pay special attention to radiator and fan clearance.
  • Firewall modifications are not expected.

Since Jeeps featuring the T18 transmission are "high-hood", clearance for classic Small Block and high Vortec (truck style) intakes and accessories is not a problem.

GM Engine Mounts for JeepsNovak engine mounts are available to ease the installation of your engine.

Novak's engine mounts, feature vibration dampening, superior strength and useful adjustability - adjustable even after the engine is installed. The design, strength, and affordability of our mounts are second to none.

Clocking Information

Our adapter is drilled for multiple clocking locations from near-factory (20 degrees down) to near-flat (3 degrees down). your body or shifters may inhibit some of these clocking options. 


Engines & Engine Mounting

GM Engine Mounts for Jeeps

Factory AMC engines already feature the recommended 1-1/4" offset to the driver's side. If marrying your T18 / T19 to a conversion Ford or GM engine, you should offset them about 1-1/4" to the driver's side for best overall results. Novak engine mounts accomodate this for several engines and Jeep combinations used with this adapter. Whatever your application, Novak likely has the perfect solution. From a 225 Buick V6 in a CJ2A to an LS3 in your JK, we’ve got you covered. 

Novak's engine mounts, featuring excellent vibration dampening, superior strength, and impressive adjustability - adjustable even after the engine is installed. The design, strength, and affordability of our mounts are second to none.


Driveshaft length changes are often required. Most conversions to these transmissions will require that the rear driveshaft be modified to be shorter and front driveshaft longer.

Some installers, concerned about the expense of new or modified driveshafts, attempt to let the existing driveshafts dictate engine, transmission and transfer case location, often to the detriment of the project. Our recommendation is to prioritize the correct position of drivetrain components over saving a few dollars which is usually regretted in the long run with compromised positioning.

Driveshaft modifications and rebalancing can be affordable when performed by driveline, RV or tractor implement specialists. New driveshafts are also an option and Jeeps that require extensive travel or specialty-built driveshafts have this option available through several fabricators across the nation. These are normally specified after placement of the new transmission and measured at vehicle ride height. As the rear driveline gets shorter, it is often advantageous to us a Double Cardan or “CV style” rear shaft with the correct geometry at the axle to minimize vibrations and possible binding. 


Use of factory axles is completely acceptable with this conversion. Axle upgrades are not necessary, but they may be chosen for reasons external to this transmission upgrade.

Also See