AX15 & NV3550 Bellhousings

There are several bellhousings available for the AX15 transmissions that mate to a variety of engines. The Aisin-Warner AX15 and Jeep NVG 3550 Transmission share a common pattern so the same applies to both transmissions.

Product & Features

The following are for the external slave 4.0L AMC/Jeep engine originally used 1993-2004. The last part number extends that to the 2006 with the addition of another CPS location, allowing replacement of the often problematic factory 6 speed.

The following are for the Dodge 3.9L & 5.2L V8 to AX15 & NV3550

The following are for the Jeep AMC 2.5L inline 4 cylinder

AX15 Transmission

These are brand new units from Aisin and are stronger than any of the original Jeep or Dodge pieces. Originally rated as a Light Duty unit, these carry a Medium Duty rating. They have been successfully used behind LS1, LS2 and the like. With proper care they are extremely strong. Included is our exclusive straight stick that may be bent to the perfect ergonomic location for your application.


Applications & Compatibility


The following transmissions will work with these bellhousings: 

  • 1994-1999 AX15 or the new Novak-supplied AX15 
  • NV3550 installs similarly as described below.
  • 1988-1993 AX15 with a new 1994-1999 style retainer

Be aware there are different rotations on the transfer case between Wrangler and XJ applications. The new AX15 we sell is the Wrangler rotation but can be machined for XJ positioning on request (no charge). Two wheel drive versions work the same as 4x4 versions on engine side of the installation procedure described here but if you want to attach a transfer case, the entire rear half, output shaft and several other pieces must be changed to allow the transfer case to bolt up. This usually makes this impractical.


The bellhousings are compatible with their respective engines. We have several adapters listed below in the links that take these to a standard Ford or GM pattern for additional applications. 


Because of its assembled length, CJ7 or longer wheelbases are compatible. Anything shorter simply leaves insufficient rear driveshaft length. Full sized Jeeps, Wagoneers and Cherokees are good candidates, especially for the stronger Novak transmission version. Just keep in mind the rating of the transmission and you’ll be fine with those applications.

Related Products

Transmission Rear Mount

The AX15 and NV3550 feature a threaded base for support and isolation of the transmission and transfer case. Factory style isolator mounts are difficult to work with in any situation other than as a direct factory replacement. Novak has engineered a universal style rear mount that is easy to affix to a variety of Jeep crossmembers and is very strong and highly adjustable. We recommend it in any retrofit situation. More info on this mount can be seen here.


Adjustable release bearing

While sometimes not needed in this application, it is priceless when clearances dictate its use. With all the variabilities in flywheel and clutch height, we adamantly recommend its use. Further information is here.


Hydraulic Clutch Actuation

If your Jeep has the master cylinder, that part can be reused. If not we would recommend this master for most Jeep applications.



The Novak adjustable slave cylinder offers several advantages over stock plastic slave pieces:

  • Billet 6061T6 hard anodized construction
  • Rebuildable, not a disposable part
  • Conventional double flare fittings allowing either our braided stainless line or standard hard line use rather than an integrated plastic failure-prone line
  • Adjustability - which is severely lacking in the stock piece



Installation Requirements

With the parts specified above, this is generally a bolt together procedure using normal mechanics tools.

Also See