Our NP435 to New Process 207, 231, 242, 241, 241OR & 249 transfer case conversion makes for a strong, refined, compact geartrain assembly both on-road and off-road, providing a compact geartrain, an excellent crawling gear, compatibility with several engines and simple installation.
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. It is drilled for over 20 degrees of transfer case clocking locations, though the provided factory angle will suffice for most New Process transfer cases.
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 your 23 spline transfer case - a 21 spline version is not available. Details below.
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.
The adapter kit is designed for compatibility with 23 spline Jeep NP207, NP231, NP242, NP249, NP241 & NP241OR "RockTrac" transfer cases. Below is a summary of spline counts and lengths usually encountered.
A more detailed discussion of New Process input gears is found here.
The 21 spline shaft is substantially weaker than the 23 spline version. 21 spline versions were only used in the 4 cylinder applications and some very early automatic 6-cylinder versions. Novak does not make a 21 spline version of this adapter kit because of this weakness, vs. the exceptional torque created by the compound low gear of this transmission.
Our recommendation is to change the transfer case input gear to a 23 spline version. See Related Products, below.
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.
Many of these conversions are for the YJ Jeeps, in which the NP435 is a terrific match. Even earlier Jeeps that are being retrofitted with the NP231 or similar later transfer cases accept the NP435 well. However, TJ and XJ Jeeps with their significant dash consoles may pose an interference problem with the NP435 shifter and top tower. The NP435 is a shorter and taller transmission than factory options in these later Jeeps. Individuals should be aware of this caveat.
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.
Our adapter is drilled for multiple clocking locations and driverâs side drop transfer cases usually clear nicely in most all applications.
Engine placement in these Jeeps should consider the following points:
Novak engine mounts are available to ease the installation of your engine if you are swapping at this time.
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.
Driveshaft length changes may be required. Chevy engines (with their rear distributors) can install around 3" further forward than AMC engines. It is also recommended that LS family engines be installed 3" further forward than the factory block (using the back face of the block as the datum point) for exhaust clearance, firewall access, etc.
Because of the engine placement and transfer case SYE kits are frequently installed with many of these conversions, you may end up with a longer rear driveshaft (very desirable for lifted Jeeps) and a shorter front driveshaft.
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.
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 âCV styleâ 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.