NV3550 into Wrangler 4.0L 1989 – 2000
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.
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 1stgear 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 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
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.
Different Packages for both the internal and external slave versions of his kit are listed below.
|NV3550 into Jeep repl AX15 w/ ext slave||$1,769.82|
|Wranglers 96-up used an external slave. 94-95 could have been internal or external, must verify. 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.|
|1||Rebuilt NV3550 Jeep 5 Speed 4WD Transmission. Dyno Tested. NO CORE CHARGE.||$1,290.00||$1,290.00|
|1||Shift Handle (NV3550)||$25.43||$25.43|
|1||Tcase shifter bracket/linkage||$34.40||$34.40|
|Clutch components: Your stock pressure plate and clutch disc will most likely work. It recommended you replace these unless they are known to be fresh|
|Clutch Kit, Jeep 4.0L – includes Release bearing, pressure plate and clutch disc||$150.00|
|Slave cylinder & Hose kit: When replacing an internal slave, this kit supplies the needed external slave, hose and adapters to the master cyl||$162.61|
|Spacer (Auto to stick conv)||$65.00|
|NV3550 into Wrangler replacing an AX15 with internal slave||Total Pkg Price||$2,072.00|
|Jeeps 89-93 used an internal slave. 94-95 could have been internal or external, must verify|
|1||Rebuilt NV3550 Jeep 5 spd 4WD Transmission. NO CORE CHARGE. One year warranty, unlimited miles. Six months if for commercial use.||Included|
|Shift Handle: You will need to modify your existing shifter by cutting off the current end, and welding on a steel plate and drilling holes thru the steel plate to bolt up to the stub sticking out of the trans.|
|Adapter / Installation kit – This kit supplies a complete new bellhousing and external slave cylinder and hose kit. This system will install easily in a Wrangler. Cherokee will require crossmember and Tcase shifter modification|
|1||Bellhousing kit incl pilot bearing, release fork & T/O. AX15 w internal Slave: Requires change to ext slave BH, and will require the stock ext slave cyl.)||
|1||Transfer case shifter bracket (NP231)||
|1||Ext Slave cylinder & Hose kit||Included|
|Clutch components: Your stock pressure plate and clutch disc may work. It recommended you replace these if you wish to ensure a proper fit. Replace in any event unless they are known to be fresh|