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Adapting the

New Process 435 Transmission

to the

Jeep Models 207, 231, 242, 249, 241J & 241OR Transfer Cases

Adapter kit for NP435 to Jeep transfer cases

Kit 431, adapting NP435 transmissions to Jeep NP 207, 231, 241, 241OR, 242, 249 transfer cases with 23 spline input gear


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 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.

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. 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.

Applications & Compatibility

Compatible Transmissions

np435_to_dana_300_overhead_view

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 NP & NVG Transfer Cases

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.

Transfer case seal spacer
New Process input gears come in varying spline counts and lengths. Whichever you have, we've got you covered. A seal spacer sleeve is included and pre-installed in your Novak adapter in the event your transfer case has a short input gear.
  • NP 231 - The NP231 may have 21 or 23 splines and a long or short style input gear
  • NP 242 - The Jeep version NP242 may have 21 splines for the 1987-1990 versions. When connected to the 4.0L HO engine (1991- ) the 242 will have 23 splines as will the Dodge and later V8 Grand Cherokee, AMG versions are 32 splines long
  • 249 - The NP249 always has 23 splines, but may have a long or short style input gear
  • 241OR - The RockTrac will always have a 23 spline, short style input gear. Its gear is unique and not interchangeable with any of the other versions due to the lower 4:1 ratio
  • NP207 - The NP207 may have 21 or 23 splines. Many versions feature extra-long input gears whose stick-out lengths (as measured from the front edge of the input gear to the transfer case front mounting face) longer than 2.2". These will require shortening with a cut-off saw and/or lathe and finished with edge breaking chamfers. New 23 spline NP207 input gears are available in Related Products below.

A more detailed discussion of New Process input gears is found here.

No 21 Spline Version?

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.

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.

Compatible Jeeps

np435_with_433_bellhousing_package

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.

Related Products


Urethane Rear Mount for Crossmember

Urethane Rear Mount, #RMU

This rear mount bolts direct to your Novak adapter, and can be used with a variety of crossmember styles.

Rebuild kits, gaskets and other parts for your NP435

Many customers choose to rebuild their 435 while installing a new mainshaft. Novak's master rebuild kits for the NP435 are the most complete on the market. Or, if you need gaskets or other parts, click here.

Pilot Bushings

your transmission will require a pilot bushing to your engine of choice. See the various options, here.

NP231 transfer case parts

NP231 rebuild, repair and upgrade parts

Some transfer cases are due for a re-seal or even full rebuild. We carry the world's most full-featured kits and components, here.

NP242 transfer case parts

NP242 rebuild, repair and upgrade parts

Some transfer cases are due for a re-seal or even full rebuild. We carry the world's most full-featured kits and components, here.

Shifter Kits for New Process Transfer Cases

As this combination will frequently be paired with Jeep New Process chain drive transfer cases (NP231, NP242), this shifter kit will make the conversion go not just smoother, but will improve your shifting action and reliability significantly over factory. Read about them here.

1976-1986 Jeep floor tunnel cover

1976-1995 Jeep CJ & YJ Floor Tunnel Cover

Start with a clean slate tunnel cover for your 1976-1995 Jeep CJ / YJ floor. Cut your shifter holes and install boots onto it as required. Material is aluminum. Can be painted. More info here.

435 Shifter

Shifters for the NP435

Truck shifter sticks that may have come with your NP435 are often too long and bend oddly for installation into a Jeep. Get a fresh start with a straight stick that you can bend to match your own ergonomics. See them here.

Shifter Retention Kit, SM420, SM465, T176, NP435

Kit, shifter retention, SM420, SM465, NP435, T176 transmissions, #SLR-176K

This shifter retention kit and mini-boot will lock in your shifter stick and give it a better barrier than factory from dust and water ingress.

Billet PTO Cover

Kit PTO-K, PTO cover, six bolt style, billet

This is the rigid PTO cover that every Novak-built transmission gets, and we recommend them to our customers. They seal better and stay that way for far longer than the stamped steel versions from the factory. Stainless button-head fasteners are included.

Transfer Case Input Gear, 23 Spline

Gear, input, New Process 23x & 24x transfer cases, 23 spline, long input, wide bearing, early gear cut, 1.5” pocket bearing, #23LWES

If you have a 21 spline input gear in your early (1988-1993) New Process 231, 242 transfer cases, swap it for this gear. Read more about these gears, here.

Transfer Case Input Gear, 23 Spline

Gear, input, New Process 23x & 24x transfer cases, 23 spline, long input, narrow bearing, late gear cut, 1.5” pocket bearing, #23LNLS

If you have a 21 spline input gear in your late (1994-2006) New Process 231, 242 transfer cases, swap it for this gear. Read more about these gears, here.

NP207 Input Gear 23 Spline

Gear, input, New Process 207 transfer case, 23 spline, long input, #716096

This is a new 23 spline input gear for your NP207 transfer case. As many of these were 21 spline models from the factory, this permits the upgrade to the stronger 23 spline design for compatibility with the Novak adapter kit.

Slip Yoke Eliminator for NP231 Transfer Cases

Heavy Duty Slip Yoke Eliminators for 231 Transfer Cases

Upgrade and shorten your NP231 output shaft to handle the increased torque of your new gears, and improve the driveshaft angle, especially important for lifted Jeeps. View the SYE kit that will work best for your situation.

Ford Engine Mounts for Jeeps

Engind mounts for Ford engines into Jeeps

This conversion will often be done in conjunction with a Ford engine. Engine mounts are available for these here.


Installation Requirements

Tools

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.

Clocking Information & Driveshaft Clearance

Our adapter is drilled for multiple clocking locations and driver’s side drop transfer cases usually clear nicely in most all applications.

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.

GM Engine Mounts for JeepsNovak 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.

Driveshafts

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 “CV style” rear shaft with the correct geometry at the axle to minimize vibrations and possible binding.

Axles

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