ax-15 vs nv4500 for 5.3 vortec

[jeepbonehead]

i have and ax15 but am thinking about buying a NV4500 for a 5.3 vortec i'm swaping. does anyone know how the ax15 and nv4500 compare in strength? does anyone keep there ax15 in there jeep with v8 power?

[SanDiegoCJ]

There is NO comparison on strength. The NV4500 is vastly stronger.

http://www.novak-adapt.com/knowledge/ax15.htm

http://www.novak-adapt.com/knowledge/nv4500.htm

NV4500's were put behind Cummins diesels in Dodge trucks.
The AX15 would have exploded trying to handle that type of torque.

[Beat95YJ]

If you want a closer ratio 5 SPd look at a nv3550

[RANGERROD]

4500 hands down stronger. chevy version has good granny gear great for crawling dodge version isn't as good but still better than ax-15.

[Jakesteramalamajama]

The AX-15 is a decent transmission. The NV4500 is pretty much indestructible in something as light as a SWB Jeep. Get the early Chevy version for the 6.34:1 granny low. Later versions can also be converted to the lower gear (or bought converted new). Even the later ones have a much lower first gear than the AX-15.

The bad: they expensive, heavy, and long. Not too long for a TJ/YJ though.


HTH,
Jake

[jalbrecht42]

Originally Posted by jeepbonehead

i have and ax15 but am thinking about buying a NV4500 for a 5.3 vortec i'm swaping. does anyone know how the ax15 and nv4500 compare in strength? does anyone keep there ax15 in there jeep with v8 power?

A friend of mine is repowering his jeepster with a 5.3. After a fair bit of research he decided to go with the AX15 and I think it's a good choice, I would do the same and may just do that in a future project I've been planning.

I have another friend who had a 4.0/nv3550, but went to a NV4500 with his 5.3 TJ swap. He did it mostly because he walked into an amazing deal on the NV4500, and as mentioned, it's pretty much bulletproof in a TJ with a 5.3.

-From what I can tell, they the AX15 is rated for the same torque as an NV3500 or NV3550 (300ft-lbs is the number I remember reading, but don't quote me on that). I mention this because I've got a NV3500 in my fullsize chevy with 4.8, I tow with it, I drive it hard now and then, and I've got 100k on it. Having said that, there is probably a reason it wasn't available behind the 5.3. You could get them with the old TBI 350's though.

-The AX15 seems to have more aftermarket support than the 3500. For example:

RSG Terminator I recall their torque rating on this modified trans being well beyond 300ft-lb (one web search said 385ft-lb) but I don't see any claims on their website now.

-I also believe that with some parts swapping they can use the different 1st gears from the toyota turbo Aisin R151 (about 4.3:1) or (another toyota transmission, I forget the name) but it's somewhere around 5:1.

Don't get me wrong, the NV4500 is stronger (I found claims of ~460ft-lb torque rating on the web) and has a wider gear spread. But the AX15 is smaller, lighter, cheaper, more fun to drive and with the right t-case/axle gearing I think it will do the job. It's what I would pick, but I know how I drive, I can't speak for you!

[himarker]

I can personally say that the nv4500 will hold waaay more than 460ft/lbs. I was putting over 800 through mine in my 98 dodge 2500 with a modified cummins. I've seen them hold way more than that too. They are a great trans, ill run one when I do the swap.

[wushaw]

The NV4500 is a great tranny, I have one in my Jeep, it is not like a NV3550, it is a true truck tranny. It is not a easy swap but well worth it if you want brute strength.

[ky scrambled]

Other then the fact that the NV doesnt like 5th gear towing they are great trannys.

[SanDiegoCJ]

Originally Posted by jalbrecht42

Don't get me wrong, the NV4500 is stronger (I found claims of ~460ft-lb torque rating on the web) and has a wider gear spread.

I know they're rated at 460 ft/lbs because that was the factory trans in my
Cali version of a 2003 RAM3500 with the Cummins. The Cummins was rated at 460 ft/lbs output.

[tbuff02]

Originally Posted by SanDiegoCJ

I know they're rated at 460 ft/lbs because that was the factory trans in my
Cali version of a 2003 RAM3500 with the Cummins. The Cummins was rated at 460 ft/lbs output.

i maybe wrong, but i don't think an automaker would put a tranny in that is only rated for 460 ft/lbs when they engine puts out that much. the tranny would not hold up to that. the ax15 is rated for 300 ft/lbs + and a 4.0 only puts out 220ish...

[jalbrecht42]

Just to be clear, the point of my post wasn't that the nv4500 is only rated for 460ft-lbs (and again, I'm not even sure if that's right, that's just a number I've seen in several places on the internet). I'm not really sure how a manufacturer arrives at a torque rating for a trans, the number certainly isn't the point where the trans will break, but rather a number that allows for some amount of longevity at that level.

[Jakesteramalamajama]

A few things:

Driveability: they don't shift quite as nice as a car transmission (ala AX-15), but they shift MUCH nicer than the older granny boxes (BW T-18, Muncie SM420/465, NP435, etc.). They are not difficult to drive on the street at all. Since it's basically a 3-speed with a granny low and an overdrive, the ratios are widely-spaced (especially on the old Chevy version) but with a big v8 and proper gearing for your tire size, you hardly notice.

Regarding the reputation they have for 5th gear going out: I think this was due to a design quirk/resonance peculiar to the Cummins 6BT where it would eventually work something loose on the OD shaft. This would not be an issue in a Jeep.

Price: They can be had used for under a grand. I only paid 900 for mine (early Chevy W/6.34:1 granny low), including the bellhousing.


HTH,
Jake

[SanDiegoCJ]

Originally Posted by tbuff02

i maybe wrong, but i don't think an automaker would put a tranny in that is only rated for 460 ft/lbs when they engine puts out that much. the tranny would not hold up to that. the ax15 is rated for 300 ft/lbs + and a 4.0 only puts out 220ish...

That's what they did though. The NV4500 was good for lots more than 460 ft/lbs. The rating was very conservative.

NV4500 Heavy Duty versions have an 11/4” – 10 spline input shaft and have an increased input torque rating of 460 ft-lb.

http://www.mackstrans.com/NewVentureID.html