XJ ax-15 to 6 spd NV swap

nitro450exp · Jul 1, 2009

Hello all,

Searched but no joy! :helpme:
Have a '94 XJ with tired AX-15.
Instead of rebuilding AX am thinking a NV 6 spd swap.
Either from a rubi or Wrangler.
Are the Wrangler and Rubi the same Tranny ?
What is the output spline count on the NV Tranny ?
Will it bolt up to my Tera 4:1 case ?
What other concerns, bellhousing, clutch, length, shifter etc.

Thanks in advance.

Nitro450exp

badron · Jul 1, 2009

Are you talking going from the AX stick to the NV 6 spd slush-o-matic? There has been no 6 speed NV stick used in a Jeep. The NSG-370 is the curent 6 speed stick used in the Jeep and that isnot a drop in for early year. This is for more info on the AX to NSG-370 swamp.
http://forums.jpmagazine.com/70/800033/jeep-transmission/six-speed-transmission/index.html

tbburg · Jul 2, 2009

One other consideration: Both the AX-15 and NV3550 were optioned in the XJ and the TJ, but they weren't the exact same transmissions. The transfer case adapter(the rear transmission case) had the bolt pattern "clocked" lower for the XJ. Swap a TJ transmission into an XJ, and everything bolts up fine, but the transfer case hits the floor of the XJ.

The NSG370 was never offered in the XJ. The Xfr case bolt pattern will be clocked to fit a TJ, and there may not be enough meat on the back face to re-drill the holes down lower. You might end up getting a clock ring from AA or some other solution. Just something else to look into.

zluster · Jul 2, 2009

A hammer works well for making the Transfer case fit against the floor.

tbburg · Jul 2, 2009

zluster said:
A hammer works well for making the Transfer case fit against the floor.

Yes a hammer works wonders from the bottom up. From the top down, it can make the stock driver's seat mount a little hard to fit back in.

Yes, you can work around it, but the OP did ask about problems/concerns with doing the swap.

Char-Broil · Jul 3, 2009

Has anyone on here actually done this without re-clocking from the wrangler clocking position? Thanks for the link to the JP forum, that has some valuable info on it. Seems like other than the CPS, getting it in an XJ would only require floor modification or re-clocking...Hopefully I'll be doing this within a year or so.

smccollamjr · Jul 3, 2009

FYI...6th gear in the NSG370 is lower than 5th on the AX15. i.e. you will be turning more RPMs with the NSG370 than with the AX15 at the same speed in top gear. A friend of mine has an NSG370 in his stock LJ w/ 4.10s. He told me he liked the AX15 in his old TJ better for trial riding.

BlueCuda · Jul 3, 2009

I have heard the same thing. A friend of mine has an 05 Rubi with the 6 speed and he doesn't like it. Says you shift way to much and it turns to much RPM on the highway. He likes another friends AX-15 equiped rubicon better.

Char-Broil · Jul 4, 2009

BlueCuda said:
I have heard the same thing. A friend of mine has an 05 Rubi with the 6 speed and he doesn't like it. Says you shift way to much and it turns to much RPM on the highway. He likes another friends AX-15 equiped rubicon better.

Did this guy swap an AX-15 into a rubicon?

Found this info on Novak's site. Just for comparison

NV3550: 4.01, 2.33, 1.39, 1.00, 0.78, R3.57

AX15: 3.83, 2.33, 1.44, 1.00, 0.79

NSG370: 4.46, 2.61, 1.72, 1.25, 1.00, 0.84, R4.06

BlueCuda · Jul 6, 2009

I was wrong about the ax-15 meant to just say 5-speed

nitro450exp · Jul 6, 2009

Thanks for the info.
Looks like the NV3550 is what I am looking for.
Sounds like an easy swap if I can find one from an late model XJ.
I like the taller 1st gear.
I trailer my XJ so top gears have little or no meaning.
The Tera case is limited to 3000 RPM so high revs should be no issue.
Thanks

NXJ · Jul 7, 2009

nitro450exp said:
The Tera case is limited to 3000 RPM so high revs should be no issue.

Say that again?

nitro450exp · Jul 7, 2009

NXJ.

I quote from the Tera 4:1 installation instructions:
" High RPM Warning
Do not exceeed 2500 - 3000 RPM for sustained periods of time when using the Low231 in low range. ----- It is possible for input speeds to reach 6500 RPM and cause damage to the transfer case " from the horses mouth.
Go the the Tera web page and download the destructions and see for your self.

tbburg · Jul 7, 2009

nitro450exp said:
...,I quote from the Tera 4:1 installation instructions:
" High RPM Warning
Do not exceeed 2500 - 3000 RPM for sustained periods of time when using the Low231 in low range. ----- It is possible for input speeds to reach 6500 RPM and cause damage,...

Wait,...

What?

3000 engine rpm X 3.83:1 first gear(AX-15) = 783 T-case input rpm.

if 6500 RPM is max sustained input RPM for the Tera case, The 1st gear limit would be about 24,890 engine RPM, or just over redline. :roll:
2nd(2.33) - aprox. 15000 rpm
3rd(1.44) - aprox. 9300 rmp

I think that might be a warning about excessive Engine RPM, not a limit on the transfer case.

Char-Broil · Jul 8, 2009

Wouldn't this apply to any transfer case? Seems to me that any driveline should not be seeing input speeds of 6500 rpm. Either way, not really an issue unless you are romping it in 4th gear and low.

BlueCuda · Jul 8, 2009

So am I the only one thats been well into overdrive while in 4 low

? Sometimes the trail opens up and I let the stroker eat a little. Its not good for anything but its fun.

Char-Broil · Jul 9, 2009

BlueCuda said:
So am I the only one thats been well into overdrive while in 4 low ? Sometimes the trail opens up and I let the stroker eat a little. Its not good for anything but its fun.

That's usually when I'll pop it into 4 Hi and decorate the jeep behind me. :clap:

nitro450exp · Jul 16, 2009

Guy's

I quoted directly from Tera, did not say I agree with it.
If you look at the destructions from Tera, they explain how they get to the 6500 RPM number, I did not quote the whole quote, hence the ------.
I did not feel like typing that much.
I also spun the crap out of my case last weekend, in first, too the rev limiter (~ 5600 RPM).
I must say though, I had to replace the input gear in my case last year.
It was a combo of design flaw, lube and RPM's that caused it to fail.
So there may be some truth to there warnings.
As always the truth lays somewhere in the middle.

Cheers

PS: Added the link to spinning her pretty hard, yes I did get out !

http://www.youtube.com/watch?v=xNhBW-4gm0s

XJ ax-15 to 6 spd NV swap

nitro450exp

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tbburg

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zluster

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tbburg

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Char-Broil

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