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Crate AX15 from Novak

OzzyXJ

OzzyXJ

NAXJA Forum User
Location
Minturn, Colorado
Hey y'all...

I'm doing a build out on my XJ and I recently fried my 12,000 mile old rebuild. I hate doing things multiple times, including swapping transmissions, so I decided to pony up and buy a Novak Adapters brand new crate AX15. I have done tons of searching online and can't find anyone that has bought a crate AX15 from Novak and thrown it into an XJ, so I'm wondering if anyone here has?

I'm marrying the Novak tranny to a crate HD np231 super shorty transfer case, all brand new, as well. Anyone running one of these? I'm fairly confident in my purchases, but I'd love to hear some opinions from people that are running them.

Thanks!
 
I'd imagine novak is going to sell you a quality unit but I'd be afraid spending that much money to put it in a jeep that just destroyed a rebuilt trans?
 
I was more concerned about the shop that did the rebuild. I would imagine that the Novak unit would be pretty solid. I didn't really do anything to the rebuild that would speed along its demise...babied it. It drank Amsoil Severe Gear GL4 75w90. The only thing I may have done was to put just slightly too heavy a lube inside it for this climate. I'm thinking I'll go with Redline MTL for my new one.
 
OzzyXJ said:
I was more concerned about the shop that did the rebuild. I would imagine that the Novak unit would be pretty solid. I didn't really do anything to the rebuild that would speed along its demise...babied it. It drank Amsoil Severe Gear GL4 75w90. The only thing I may have done was to put just slightly too heavy a lube inside it for this climate. I'm thinking I'll go with Redline MTL for my new one.
Click to expand...

tarts what killed it the 75w-90 gear oil. you should have been running 10w-30 motor oil in the thing. we have used mobil 1 for a while in one of ours with good results so far.
 
The gear oil is fine as long as it is yellow metal safe. I am not sure amsoil is.

What failed in the old transmission? Bearings? Shop did something wrong. Synchros? Your oil probably killed it.

I would get a junkyard unit, rebuild it yourself, and put it in honestly. You will pay less for most of the tools needed, the parts, and the junkyard transmission than you would for a brand new transmission OR a professional rebuild most likely. AX15s are not complex, they're fairly simple and well documented in the service manual.
 
I purchased an AX-15 from Novak a couple of years ago. I also got the Hurst shifter that was optional. That Hurst shifter is absolutely wonderful; very short throw, extremely crisp shifting.

Only thing that happened is that they sent me an AX-15 for a TJ, instead of an XJ. The TJ trans will fit, but it causes the transfer case to clock further up. This isn't a problem with a 231, but a 241OR will not fit without extreme massaging of the floor tunnel.

Let me know if you want more information.

David Bricker / SYR
 
Synchros failed in my latest transmission. The guy that sold me the transmission from Novak told me that I could definitely use a lighter gear oil, given our cold climate in the central Rockies. I'm not convinced that the Amsoil I used is yellow metal friendly. Red Line states that their MTL is, though. I'm not sure I really want to go with a 10w30.


David Bricker you enjoy your transmission? I didn't get the Hurst shifter, but I did buy their aftermarket cable shifter for the NP231. That horrible factory Z Gate shifter is part of what did my last NP231 in...well that and grenading it in Moab! :)
 
I have redline MTL in my ax15 and drove around Virginia during the recent snow storms here and it took a few minutes to get it warm but after that it operated like it would a summer day.
 
I've used Penzoil Syncromesh for nearly 250k miles without an issue. It's at every auto parts store out here.
 
blondejoncherokee said:
tarts what killed it the 75w-90 gear oil. you should have been running 10w-30 motor oil in the thing. we have used mobil 1 for a while in one of ours with good results so far.
Click to expand...
mine had 75-90 in it for ages and was fine.

Ronbo said:
I've used Penzoil Syncromesh for nearly 250k miles without an issue. It's at every auto parts store out here.
Click to expand...

this.

my junk had syncromesh in it for a long long time. Winter, summer whatever. 4 years of daily driving and a few more years of beating it on the trail.
In the winter time the 2nd to 3rd gear shift was a bit stiff until it warmed up, other than that, no issues.

It's still wheeling today.
 
I've never considered using 10w30 until very recently, and now I get it. I know dudes in the deep south that are doing some serious wheeling in that serious southern summer heat, using 10w-30, and they're fine. Really makes the case.

That being said, only one other person here has installed and used a Novak crate ax15 tranny in their rig. I'm inclined to think I'll be fine, but it's interesting to see what NAXJA says.
 
I am running Pennzoil Synchomesh fluid in my Novak AC-15. Been a couple of years, shifts great. But, Gomer sees exclusively warm (or hot) weather. I'd consider 10W-30 in the colder climates.

I will say the trans shifted quite stiff when brand new. I think part of that was the Hurst shifter, and it's significantly shorter throw. Now, it still shifts firm, but not excessive, and the shift gates are quite well defined. It shifts crisper than my MazdaSpeed6 in some ways.

I also got the cable shifter for the 231, which we moved over to the 241 when it went in. Novak was able to provide an extended cable when we installed the Black Box, so linkages are made quite easy with that cable.

David Bricker / SYR
 
OzzyXJ said:
Hurst shifter? I looked on Novak's site and couldn't find it...can you supply a link?
Click to expand...

You may need to contact them. I remember that after I bought my transmission, the Hurst shifter became optional. At the time of my purchase, it was included, but they made it optional to reduce the price of the trans package a bit.

The standard shifter has your fingers nearly hitting the dash in first, third and fifth gears. The Hurst comes nowhere close. Without measuring, I'd say the Hurst shifter throw is a good 3 inches shorter.

Just be sure to make sure they send you an XJ transmission of you ever intend to put a 241OR in your rig. The upside to the TJ transmission clocking is that you can run a flat belly pan with a 231. My belly pan just has a 2" dimple in it for the 241OR. But, that came at the expense of some serious hammer work.

David Bricker / SYR
 
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