New Process / Dana 300 Flanged Transmissions
Jeep & IH Models 18 & 20 Transfer Cases
Adaptation of newer Jeep four & five-speed transmissions into earlier Jeeps is now feasable.
This kit is only intended for Jeeps that have the length necessary to accomodate these longer transmissions.
The Novak #152 adapter is 2" long. While this is very compact for a twin-bearing adapter, the mating transmissions may prove long for some early Jeeps. For your reference, some combined lengths include:
- AX15, 18-1/2"
- NV3550, 18-1/2"
- T176, 16-1/2 "
- T5, 17-1/2"
- TF999, 24-3/4"
- AW4, 27-3/8"
Most of these lengths will not be appropriate for an early CJ (pre-1972) with short wheelbases, unless the engine is a V6 and has been installed in as far forward a manner as possible.
The adapter is machined from corrosion resistant 6061 aluminum. The included adapter shaft is available as a 23 spline input only.
The following transmissions are possibilities for such a conversion:
Transfer Case Input Gear & Overdrives Information
Our adapter output shaft is splined for either six-spline input gears, only.
- Six-spline gears (as seen, right) are predominately most common, as found with the Jeep T84, T90, T86, T89, T98, T18, T15 & T150.
- The rare ten-spline version is only availalble on the 1966 - 1974 transfer cases against the Jeep T14 transmission.
- Factory Jeep TH400 to Dana 20 combinations had a fifteen-spline input gear, which must be replaced by a compatible six-spline version.
- International Harvester Dana 20's that had the TF-727 automatic had a 23-spline input gear, which must be replaced by a compatible six-spline version.
Consult our informative Dana gears interchange chart if necessary.
All Warn type overdrives are compatible with this conversion. Spline count information is the same.
Transfer Case Bore Size
The diameter of the transfer case center input locating bore will be either 3-5/32" or 4".
- Most Dana 18's have a 3-5/32" bore, including those found against the T84, T90, T89 or T98.
- Some Dana 18's have a 4" bore, including those found against the T86 & T14 transmissions (Buick V6 engines), 1966-1971.
- All Dana 20's have a 4" bore, regardless of the transmission they were joined to.
Transfer Case Strength and Condition
The Dana transfer cases are very well matched to the 700R4. They are uncommonly strong, compact and servicable. They are capable of power ranging up through V6s, V8s and even the Chevy Big Blocks.
It is not requisite that you rebuild your transfer case to successfully complete the conversion, but it may be a good time to do so if your transfer case leaks or has many miles of service. We've made our Dana 18 & 20 gaskets & seals kits and our all- inclusive master rebuild kits available for this purpose.
Transfer Case Shifter
This transmission conversion will allow for the retention of the factory Dana 18 twin-stick shifters, Dana 18 single-stick shifter, and essentially all of Dana 20 shifters, including this twin-stick shifter kit.
Driveshaft length changes are nearly always required for this conversion, as this geartrain combination is typically longer than factory Jeep combinations.
Some of our customers, fearful at the perceived expense of new or modified driveshafts, attempt to let the existing driveshafts dictate engine, transmission and transfer case location, sometimes to the detriment of the project. Driveshaft modifications are usually inexpensive when performed by driveline, RV or tractor implement specialists. New driveshafts are an option but seldom a requirement in regards to the actual successful conversion. Jeeps that require extensive travel or specialty-built driveshafts have this option available through several fabricators across the nation.
|Our RadLock radiators offer an available integrated transmission cooler, to greatly add to the life of your HydraMatic transmission.|
For every ten degrees cooler you can keep the transmission, you can add 25,000 miles to its service life. Therefore, use of a transmission oil cooler is advisable for this automatic transmission.
Use of a transmission temperature gauge is also a good idea. These are widely available and generally inexpensive.
We will suggest the use of our RadLock high-performance conversion radiators, which can include an integrated transmission fluid cooler. You may also use a standalone / supplemental transmission cooler depending on your driving style and climate conditions.
Engines & Engine Mounting
These transmissions can be installed in conjunction with an engine conversion into the Jeep. These engines may include the Chevrolet Small Block V6 (1997-2005), V8, and Gen. III+ V8 (1997- ).
In any scenario, it is critical that the engine be installed (as the Jeep engines usually are) with an offset of 1" to 1-1/2" to the driver's side. Other engine mounts on the market - especially the bolt-in versions - do not take this into account and make other placement decisions for the installer that do not take the full powertrain into account. Novak offers what we have found to be the most intelligent engine mounting system for Jeeps available, allowing the installer to make an easy and satisfying decision as to powertrain placement with the new transmission and the Dana transfer case both considered.
|Novak's MM Series 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.|
|Advanced computer modeling methods were integral to the design of our #152 adapter assembly.|
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.
|While it is mechanically possible to run the overdriven transmission against a Dana 18 that features a Warn style overdrive, consider that you'd have an overdrive ratio of 50% (25% + 25%). While this is a fascinating thing, theoretically, the velocities that it could turn within your Dana 18 could be overwhelming. You might try it for the sake of science, but don't expect to get much life out of your Dana 18 - or any other power transmission component within or behind it.|