I'm lookin at a rebuild on my AX-15, this crap happens at the worst possible times. Anyway I got to thinkin this would be a good time to swap in a better transmission. One that will be good for a V8 down the road. I've looked at several different transmissions & have had my eye on a NV4500 but which one(Dodge or Chevy) would be cheaper to bolt inbetween a 4.0 & np231? What other heavy duty manual transmissions are out there?

If your set on a 5speed the 4500 sure specs out nice all synchro, granny first and OD, but, The 4500 is longer than the ax15 so forget about any useable rear driveline unless you move the rear axle back about a foot.

future V8 and granny low in front of a 231? forget that and start thinking A2 or something shorter. mebbe a flipped 300 (please lets not start that debate again)

Got Cash? I hope so, this is starting to sound expensive.

do you need 5th gear?
do you need syncro first and reverse?

if not forget the pricey 4500 and think SM 420 or NP435. checkout h8monday's setup (or whatever drunkenBendHerOverDownUnder name he has this week)

or just rebuild that aisin while your thinking about it.

What about a nv3500? not as strong as the 4500 but better than the ax-15 and a 27% overdrive. I have a nv3500 from a TJ with less than 20K on it for $650 Can. Then down the road you can bolt up a 300 just buy putting on a clocking ring or grinding the output shaft 1/8 inch. You can use your ax-15 bellhousing and clutch and i will throw in a shifter.

I was set on a 5 speed. The AA engine swap book has the NV4500 listed as being shorter than the AX15, by 5" I believe. The np231 wouldn't be there in the future. I hadn't really considered the nv3500 that much of an upgrade from an AX15. I'm gonna hit some transmission shops next week & see what happens. I'll probably go with a rebuilt cause I gotta get rollin asap.

maybe I'm wrong on the 4500 but I thought it was a few inches longer than the ax15 when all ready to go.

here is awritup (http://www.off-road.com/jeep/reviews/yj1-nv45003.htm) that states
"The NV4500 assembly is longer that the stock AX15 and this necessitates driveline"

not sure what all they did with adapters and bellhousing etc so that can be part of it.

The only dimensions I've found are case length of 12.37" and an extension housing length of 6.5" but I can't find overall assembly length.

The measurements listed in this book are

NV4500
12.37" case length + 6.50" output shaft length = 18.87"

AX15
16.75" case length + 8.00" output shaft length = 24.75"

I don't know though because this book conflicts itself several times. In another place it says the AX15 overall length is 24" with an input shaft length of 7.5". It says the overall length for a nv4500 to bolt to a 4.0 as an AX15 replacement to be 25.85" long using the original AX15 bellhousing or use an AA bellhousing to cut 1.125" off the overall length. Confused yet?:rasta:


EDIT: After reading that page I guess it is longer & looks like it cost to much $$ for me now along with a lot of time, both of which I don't have. Rebuild it is, gotta have OD.

Why not go with the SM420? Short, beafy, and it has a granny low of 7.05:1 :D Your not going to have any problems with a v8 turnin it because it is rated at 2.5 tons! Just make sure that you have a good shop rebuild it for you because I have been screwed twice! f*ckin bastards:flipoff2:

How about a Clark tranny? I think its model 280vo that has a granny first and an overdrive. There is a company called Performance Gear that rebuilds and adapts them, supposed to be a bit cheaper than a 4500. These ran in dump trucks and busses, so strencth shouldnt be an issue. Just another option to consider.

Ken