NV3550 vs AX15: Which Is Better?

The NV3550 and AX15 are two transmissions that were used in a variety of vehicles from the late ’90s and early 2000s, most notably Jeeps. These two transmissions are pretty comparable in terms of the power they can handle, although it may be easier and cheaper for you to get your hands on an AX15.

NV3550 Overview

The New Venture Gear 3550, also known as the NV3550, is a manual transmission released for the TJ Wrangler and XJ Cherokee in the year 2000, as well as some Dodge pickups. The NV3550 was actually created as a replacement for the AX15, but compared to the AX15, the NV3550 didn’t last nearly as long before it was replaced with something else (only four years).

The NV3550 is a 5-speed transmission, where the fourth gear functions as a direct drive gear and the fifth gear is an overdrive. All of its gears are synchronized, and the gears are helically cut. There were different versions of this transmission made for 2WD and 4WD vehicles.

The NV3550 isn’t the beefiest transmission out there, but it was designed to be tough enough for most stock applications. According to Jeep, the NV3550 is designed to handle about 300 lb-ft of torque. The NV3550 is an adaptable transmission and can be used with a lot of different engines with minimal extra work.

The NV3550 is compatible from the factory with the classic Jeep 4.0 inline-6, of course, but there are also conversion kits available that allow you to connect this transmission to the Buick V6, the Chevrolet small-block V6 and V8 engines, and the Ford I6 and Windsor V8 engines.

AX15 Overview

The Aisin AX15 was first introduced in 1988 and appeared in a number of different Jeeps, including the YJ and TJ Wrangler, the XJ Cherokee, the ZJ Grand Cherokee, and the MJ Comanche. This transmission was also available for the Dodge Dakota, and it is also closely related to the R154 transmission that came in the third-generation Toyota Supra Turbo.

The AX15 was a popular and long-lived transmission, and it saw production from 1988 all the way up until 2000. Even today, the AX15 is a popular transmission for people looking to swap a new one into their vehicles, due to the fact that this transmission is plentiful, cheap, and known to be quite durable and reliable.

Like the NV3550, the AX15 is a 5-speed transmission with a direct drive fourth gear and an overdriven fifth gear. Also, like the NV3550, the AX15 is fully synchronized and uses helically cut gears, and there are both 2WD and 4WD versions of this transmission.

Performance-wise, the AX15 is very similar to the NV3550, with a torque rating of 300 lb-ft. Other similarities to the NV3550 include the fact that this transmission can be mated to a number of different engines.

The AX15 came standard with cars that used the AMC 258 and the Mopar 4.0 inline-6 engines, but with a little bit of tweaking, you can connect your AX15 to the following engines:

  • AMC I6 and V8 engines from 1972-1991
  • The Chevrolet V6
  • The Chevrolet small-block V8
  • General Motors’ Generation III V8s
  • The Ford Windsor V8
  • The Ford I6

Comparing the Two

Frankly, the comparison between these two transmissions is pretty close. Both of these transmissions are pretty similar in terms of their torque ratings, size, number of gears, and the vehicles they were used in.

Probably the biggest difference between these two transmissions is their first gear ratios. The NV3550 has a first gear ratio of 4.01, while the first gear ratio in the AX15 is 3.83. This makes the NV3550 a slightly better transmission for offroading since a higher gear ratio is better for crawling.

Some individuals also report that the NV3550 is smoother to shift and makes less noise while driving than the AX15, which makes sense considering it’s a newer transmission. If this makes a big difference to you, the NV3550 is probably the transmission to go for.

The main benefits of going with the AX15, on the other hand, are that the AX15 is considerably cheaper than the NV3550, due to the fact that it’s an older design. The AX15 was also in production for much longer than the NV3550, so if you’re doing some junkyard hunting for a new transmission, you’ll probably be more likely to find an AX15.

Overall, both transmissions are very solid options, so you’ll probably be fine with whichever one you’re able to find.


The NV3550 and AX15 are two very similar transmissions with only a few real differences between them. Long story short, the NV3550 has a higher first gear ratio that makes it a bit better for offroading applications, while the AX15 is cheaper and easier to acquire.

Whichever transmission you go with, however, you can expect it to be reliable and durable, as that’s what both of these transmissions are known for being.