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Adapting

AX15, AW4, NV3550, NSG370, Etc. Transmissions

to the

Jeep Dana Model 300 & FSJ NP Transfer Cases

New Process style flange transmissions are adaptable to the Jeep Dana 300 with the use of Novak's #153 clocking ring or #153F flip ring. These transmissions include the 4wd versions of the AX15, AW4, 904/909, NV3550, and NSG370.

This adapter is compact at only 7/8" long. The adapter itself is machined from aluminum alloy. Unlike thin, budget clocking rings, this adapter features precision index centering for long spline life, instead of relying on bolt locating. Additionally, the Novak #153 features 7/8" of thread engagement, in lieu of an inadequate 3/8”.

Option I: Standard Passenger (Right) Side Drop Version

Clocking ring for transmissions to Jeep Dana 300 transfer cases

The 153 adapter is drilled and threaded for four transfer case angles The installer will be able to easily choose the optimum transfer case angle based on the particular installation.

This kit is also compatible with the Jeep NP 208, 219, 228 & 229 transfer cases.

Kit contents:

  • Adapter ring
  • Seal, double-lipped
  • Gaskets
  • Fastening hardware
  • Instructions
153_ring_closeup

Option II: Flip, Driver (Left) Side Drop Version

Flip ring for transmissions to Jeep Dana 300 transfer cases

The 153F Flip adapter is drilled for two possible flip angles for the Dana 300. The installer will be able to easily choose the optimum transfer case angle based on the particular installation. While "flipping" the D300 to a driver drop position is quite simple and the flip ring will do exactly what it is supposed to do, the installer needs to consider the following important ramifications:

  • Shifter linkage relocation will be required to avoid interference with the transmission
  • The expansion air vent needs to be plugged and relocated upwards
  • The draining method will need to be addressed as the factory pan and drain are now up
  • Rail seals that were designed for light dust and oil retention duty are now immersed in oil and will leak if not addressed
  • Successful conversions of this type go to extensive work to relocate the shifters above the transfer case and plug lower holes

Aftermarket companies like Behemoth, Down East OffRoad and others may offer good solutions here.

The flip version of this adapter is not compatible with FSJ New Process transfer cases; NP208, 219, 228, 229.

Applications & Compatibility

Compatible Transmissions

The transmissions listed below with the following caveat are compatible with this adapter. you may need to add and install an input shaft for your Dana 300, depending on which transmission you are using. To add one to your order, see Related Products, below.

ax15_rear_quarter_face

As an example, this AX15 features a 23 spline output shaft that protrudes past the rear face, and therefore, does not require the additional 300 input shaft.

23 spline, extended length shafts are for:

  • TF904/909
  • TF999/32RH
  • NV3550
  • NSG370

No additional input shaft is typically required for:

  • AX15, 1988-1999
  • AW4, 1991-1999

If you are unsure about which to choose, follow this rule:

  • If you have a 23 spline transmission output shaft whose end extends ~1/2" past the rear face of the transmission flange, you do not need a new input shaft
  • If you have a 23 spline transmission output shaft whose end flush with the rear face of the transmission flange, then add the appropriate 23 spline input shaft to your order

Compatible Transfer Cases

All Jeep models of the Dana 300 transfer cases are compatible with this adapter assembly. IH versions of these transfer cases are not compatible.

The Dana 300 transfer case is natively stronger than the above gearboxes and will not be the weak link in the chain. The 300 is uncommonly strong, compact and serviceable. They are capable of power ranging up through V6s, V8s and even the Chevy Big Blocks.

AX15 to Dana 300 Assembly
A bird's eye view of an AX15 with GM bellhousing adapter, #153 adapter, Dana 300 and optional twin stick shifter kit.

Dana 18 & 20 transfer cases are not compatible with this kit. However, Novak's #152 kit is.

Jeep New Process 208, 219, 228 & 229 Transfer Cases are compatible. However, don't rule out foregoing this adapter kit and using the native NP231 or NP242 transfer cases, adding an SYE kit for strength and adapting your transfer case shifter as necessary.

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 300 gaskets & seals kits and our all-inclusive master rebuild kits available for this purpose. See Related Products, below.

Compatible Jeeps

This conversion is compatible with all longer wheelbase or stretched Jeeps. Be aware that many of these combinations are simply too long to fit in shorter Jeeps, particularly those with substantial amount of suspension lift.

Related Products


Dana 300 Exended Spline Input Shaft

Shaft, input, Dana 300, 23 spline extended depth splines, factory length

Factory 23 spline Dana 300 shafts have a relief where the splines do not reach the front of the shaft. To prevent weak spline engagement, we make this version that is fully splined. Additionally, factory Dana 300 splines are often too worn. This shaft resolves that.

AX15 & NV3550 Rear Mount

Kit RMAX15, mount, rear, AX15 and NV3550 transmissions, universal & adjustable

The AX15 and NV3550 feature a threaded base for support and isolation of the transmission and transfer case. Factory style isolator mounts are difficult in situations other than as a direct factory replacement. Novak's universal style rear mount is easy to affix to a variety of Jeep crossmembers, is strong and highly adjustable.Recommended for retrofit builds.

Dana 300 rear bearing cap

Kit, Dana 300 front output rear bearing billet cap

This innovative bearing cap uses o-ring sealing around its perimeter and bolt holes, then shims the bearing internally, instead of the leaky, exposed stack-up shims. This is one way Novak builds its own leak-free Dana 300's in-house.

Dana 300 Rebuild Kit

Gaskets & Rebuild Kits for Dana 300 Transfer Cases

Replace the hard-working bearings and intermediate shaft of your Dana transfer case with one of these kits, all while sealing it up and getting your bearing endplay correct. See them and several other parts and kits here for your Dana 300.

Dana 300 twin stick shifter

Shifter kits, Dana 300 twin stick

Shifter upgrades are frequently done with a transmission swap. See our options for shifters, boots and knobs for your Dana 300, here.

Twin Stick Boot

Boot, twin-stick, textured, with stainless steel bezel

Choose this boot to use with the adjacent Dana 300 twin stick kit.

1976-1986 Jeep floor tunnel cover

Cover, transmission tunnel, CJ & YJ style, customizable

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.

Dana 300 Super Short Tailhousing

Dana 300 Super Short Tailshaft Assembly, #300RX

Strengthen and shorten your Dana 300 in one shot with Novak's #300RX tailhousing assembly. The factory output shaft is the Dana 300's fuse, and the upgrade to 32 splines and an improved driveshaft angle will make a serious difference. See it here.

Billet aluminum Dana transfer case pan

Kit D328-D, billet aluminum bottom cover pan, Dana transfer cases, deep version

A deep and rigid billet aluminum pan for your Dana 300 transfer case. More fluid capacity, better sealing and some anodized eye candy for your geartrain. Shallow version for better ground clearance also available here.

AX15 Transmission Package, New, Turn-Key

Built for Novak by Aisin Warner, this is the best rendition of the AX15, with all updates and improvements implemented over the years. Our AX15 comes complete with shifter assembly. If ordered with the above adapter kit, we will assemble and configure it for you to the maximum extent possible. See and order one here.


Installation Requirements

Tools

The 153 kit requires standard mechanics tools for installation. The D300 input will require bearings be pulled and pressed on the input, in addition to typical mechanic's hand tools.

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.

Novak Gen III+ engine mounts for 1976-1986 Jeep CJ models will remove any guesswork from the engine installation location as they are predetermined for the best location and engine clearance margins.

Driveshafts

Dana 300 AX15 shifter clearance
While there are a few clocking options available, AX15 installers will likely settle in on the sweet spot where the Dana 300 shifters nestle into the contours and gussets of the AX15 case, as shown here.

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