NV3550 conversion

Jeep supplied a Japanese made transmission called the AX15 for these Jeeps. While this is a decent trans, if it has failed, you may consider replacing it with the NV3550. This transmission is considered to be significantly superior to the AX15. 

NV4500 Conversion

There is one other popular replacement option for the AX15: The NV4500. This trans is way-oversize for the application, and requires a body lift or extensive floor pan modification to fit. The usual incentive for this conversion is to get the truck style wide ratio, almost granny 1^st gear which can be useful for offroad use. On the other hand, this conversion will make a your jeep drive more like a  truck. If this looks like the option or you, High impact does have available a package using the NV4500 replacing the AX15.  

NV3550 / Klune-V Extreme underdrive

Rather than a granny gear 4 or 5 speed, a more "premium" alternative to achieve extreme gearing would be an NV3550 combined with a Klune-V Extreme Underdrive.

NV3550 conversion Details

Internal vs external Clutch Slave Cylinder

The conversion package required for each is different: Jeeps 89-93 used an internal slave. 94-95 could have been internal or external, you must look at the bellhousing and verify (with an ext slave, you see the slave mounted to the rear of the BH off to he side, with internal slave, the hydraulic lines will disappear into the bellhousing). Wranglers 96-up used an external slave.  External slave applications will pretty much bolt-in using the stock AX15 BH, with maybe a little minor modification, and a new Tcase shifter bracket. Cherokees will also fit, however crossmember and Tcase shifter modification may be needed.

Adapting to the Transfer case

NP231 - This is the transfer case found stock in Jeeps from 1989 - 2000, and most jeeps (except Rubicon) from 200-up. Some 87-88 Jeeps will have the 231. Units that came with the 2.5L 4 cyl engine, and units that came behind the Peugeot 5spd (1987-88) will have 21 spline input gears. If you wish to retain this transfer case, you will need to replace the input gear with a 23 spline part (Listed below). The remainder of the NP231 Tcases came with a 23 spline input, and will bolt up directly to a NV3550 transmission

Atlas II Transfer Case - This case is available in configurations for direct bolt up

Klune-V Extreme Underdrive - This unit is a premium option where extreme offroad gearing options are desired. The unit fits between the transmission and transfer case. Due to the additional length when adding this unit, there are various issues that must be addressed to ensure proper driveshaft operation. While all options are not discussed, an article installing a Klune into a Wrangler YJ will give an overview. Other options combining a Klune-Atlas or Klune-Bronco Dana20 make shorter, no-compromise systems. Please call us if you are considering such a system and have concerns not covered in the website. 

Conversion Package

High Impact has available a package providing you with all the primary essential ingredients to this swap. The NV3550 will fit under the stock body without a body lift. Only minor floor pan mods are needed where the shifter handle comes up.   

Package:

*NOTE: The prices below are PACKAGE prices: The prices for the installation kit parts will be 10-20% higher when purchased separately

Different Packages for both the internal and external slave versions of his kit are listed below.

(We can also provide custom packages where needed)