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.
The Novak NP435 to Jeep transfer cases adapter is very compact at only 3.2" long for a combined transmission and adapter length of 13.9". The adapter itself is cast and machined of 356T6 aluminum heat treated alloy, featuring thick flanges, a heavy cross-section, and strength-adding gussets.
Our adapter is drilled for multiple clocking locations from near-factory (20 degrees down) to near-flat (3 degrees down). However, pan clearances and front axle width may inhibit the flatter options.
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 for purchase 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.
The kit contains aluminum adapter housing, transmission output shaft, seal, transfer case to adapter gasket, transmission to adapter gasket, fastening hardware, steel mounting, base and instructions.
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 this are available on our NP435 Knowledge Base article linked below.
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. Many consider one of our complete Novak remanufactured and upgraded transmission packages. The advantage of a superior, professionally built transmission, tested and ready to bolt in delivered to you is definitely worthy of consideration.
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.
Our usual recommendation is to replace the older style transfer case (especially the troublesome 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. Also the 242 full-time case (particularly the AMG version as it is extremely strong) has the correct side drop and allows a mechanical speedometer output. Certain part-time Dodge 241 applications will also work. These more modern transfer cases allow the use of our cable shifter assemblies for a cleaner installation, have lower low range ratio, helical cut gearing, fluid pump, and are a newer more refined design. Read more about the differences here.
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.
Any engine that can be made to work with the chosen transmission will work with this adapter. We have available parts to adapt several versions to various engines. See the NP435 information page linked below for that discussion.
This transfer case adapter's design has a structural base for an industry standard urethane isolator mount, available for purchase. This is our preferred rear mount unit. Our kits are designed for it, and its usage is essential to protect powertrain components from the flex and movement typical of any automobile, but especially Jeeps.
Whether you are assembling onto a stock crossmember/skidplate or if you are setting up a high-clearance skid plate, you will find it to be a clean and simple process.
A pilot bushing is always required for installation choose the correct version for your application from these choices
Ford Small Block Cranks
Though complete disassembly of your transmission is not required to install our new output shaft, often this is a great time to rebuild a tired or unknown unit. These rebuild kits offer the best available components, bearings, synchros, gaskets, and seals to perform a first rate rebuild along with your installation. Our instructions accompany all rebuild kits.
Straight sticks are available if yours is work or you simply want to start with a clean slate to get the bends right.
The stock D300 shifter may be used, possibly requiring minor modifications. Often it is advantageous to use a new twin stick style shifter, especially if you are able to remove the interlock pins during the transfer case rebuild process. For the Jeep Dana 300, we recommend two twin stick shifters. One features an adjustable length.
Another great option for the D300 is our Dana 300 Transfer Case Twin-Stick Shifter Kit which is a solid, high quality option but lacks the forward adjustability of the transfer case shifters. It has the option of billet knobs showing the engraved shift pattern.
All would require the
These billet aluminum, anodized billet covers seal up substantially better than the factory stamped steel covers. Check your transmission to see if it requires one or two of them.
Because the transmission and transfer case shifters are often in a different location than factory in these Jeeps, this new transmission tunnel cover gives the installer a clean slate. There are no screw holes nor transmission & transfer case shifter holes, allowing the installer to drill and cut them as necessary. An easy way to get a perfect fit is to use the old cover as a template, making cuts as necessary, then overlay on the new aluminum piece for perfect holes.
The finish is natural brushed aluminum, which looks pretty terrific, but it can easily be primed and painted to suit, if desired.
This tunnel cover is compatible only with 1976-1986 CJ Jeeps.
These rigid and precisely machined billet bottom pans are the answer to a few Dana transfer case dilemmas. The thick, smooth-finished flange replaces the thin, warped factory pans and they virtually assure a drip-free seal.
Two designs are available for the Dana 300: The shallower depth, low-profile version for Jeeps requiring greater ground clearance. This version increases fluid capacity over the factory pan by about 6 oz. The extended depth version that maximizes the fluid capacity for the most punishing service. This version increases fluid capacity over the factory pan by about 16 oz.
If you can accommodate the electronic speedometer or don’t need a speedometer option, this kit will give you the ultimate in strength and short length. Full details are here.
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.
Engine placement in these applications is an effort in compromise to find the best position overall as a package. Generally the engine will be about 1” or even more towards the left, (driver’s side in the USA) away from the front differential in a CJ application. This gives the best balance of weight, and more importantly clearance, for the driveshaft going to the front axle. Your tight spots will be steering to exhaust on the left (hold that as tight as you can) and clearance for the front driveshaft on the right. On a driver’s side drop transfer case, usually the later Jeeps, things often get a little easier as steering and front driveshaft are pushing you the same direction. Fore and aft position will vary with the Jeep model and engine.
Have a CJ5 and Gen I with a rear distributor? You’ll be better off a little forward for more rear driveshaft length and clearance for that HEI. If you are in a longer Jeep and using an LS engine with no distributor, you’ll have more fan clearance and better balance if you hold it to the rear. Usually for ground clearance tuck things up nicely for height to avoid damage to oil pans and other life giving parts in the Jeep. On later Jeeps with a Driver’s side drop transfer case and front differential, things are a little easier as the steering and offset are both pushing the drivetrain to the passenger’s side. Again, that 1 to 1-1/2” dimension is usually where you want to be. Common sense and taking a step back to look at things overall goes a long way.
Our adapter is drilled for multiple clocking locations and driver’s side drop transfer cases usually clear nicely in most all applications.
If converting to a V8 in conjunction with this upgrade, aftermarket engine mounts are available to ease its installation. Because of the broad spectrum of engines and vehicle combinations used with this adapter, it would be difficult to list them all here. 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 an option, but not necessarily a requirement in regards to the actual successful conversion if your existing driveshafts are in good condition.
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.