Questions about changing a NSG-370 6-speed to an AX-15

Long Rider

TJ Enthusiast
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May 21, 2019
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My 05 Rubi had the infamous reverse problem when I bought it last year. I have an extended warranty, so I brought it to a dealership. They had to put two different re manufactured 6 speeds in it before they said it was good to go.

It was not.

It is actually worse now. I've thought about taking it back and getting the warranty company to fix it, but they delay things so much, and I've read enough to know it's a fairly lousy transmission anyway.

Lots of people on this site recommend changing to the AX 15.
Has anyone actually done it?
Have they done it with a Rubicon?
What does it entail? (Driveshafts, clutch, etc)

Any help would be greatly appreciated!
 
My understanding is that it bolts right in without any issue at all. I could be wrong, but that's what I understand at least. Hopefully someone who has done the swap can chime in.

The AX-15 does seem to be a better choice than a replacement NSG370.
 
You're right that the AX-15 is a better choice, but it won't simply bolt in. Off the top of my head, the clutch disc has to be ax15 style and pressure plate has to be nsg370 style. The problem is that the flywheel position sensor is different with the late-model TJs, so you also need a new bell housing. This should be the right part:

https://www.morris4x4center.com/bellhousing-nv3550-to-jeep-4-0-aa-712590.html
I don't believe you'll need new driveshafts, but double check that.
 
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It would be foolish not to change the clutch when everything is torn down. With the transmission, bellhousing and clutch + fluids, I'm looking at $2,500, not counting bandaids and beer. Dang it!
 
I've had these two links bookmarked for a while regarding this as I too have an 05 rubicon with an nsg370 that is giving me issues. Going to discuss the idea with my shop in the near future, although I probably won't do anything until the end of the year since I just bought an 02 sport to be the new daily and want to do a small amount of work to that first. Would rather put something trusted in it's place instead of spending good money to fix or swap the nsg only to potentially run into more issues down the road again. Replace the ***s with wrangler forum.

https://www.***.com/f210/documenting-and-requesting-input-on-swapping-nsg370-in-2005-or-2006-tj-with-nv3550-2058697.html

https://www.***.com/f210/nsg370-to-ax15-conversion-1840642.html
 
I've had these two links bookmarked for a while regarding this as I too have an 05 rubicon with an nsg370 that is giving me issues. Going to discuss the idea with my shop in the near future, although I probably won't do anything until the end of the year since I just bought an 02 sport to be the new daily and want to do a small amount of work to that first. Would rather put something trusted in it's place instead of spending good money to fix or swap the nsg only to potentially run into more issues down the road again. Replace the ***s with wrangler forum.

https://www.***.com/f210/documenting-and-requesting-input-on-swapping-nsg370-in-2005-or-2006-tj-with-nv3550-2058697.html

https://www.***.com/f210/nsg370-to-ax15-conversion-1840642.html

I've tried to substitute *** with "wrangler forum" in practically any combination I can think of, but nothing works.
 
I've tried to substitute *** with "wrangler forum" in practically any combination I can think of, but nothing works.

Sorry, no space between the two words (wranglerforum). I know links to a couple of the other forums are blocked because they blocked links to this forum so I wasn't sure if I typed it out normally if it would also be an issue. You could stick the url with the *s in a search engine as is and it should come up too.
 
Any progress with these? I’ve been given two faulty rebuilt NSG370s and I doubt they will warranty me again. I‘m wondering if the transfer case skid is compatible or if I need one from the correct vintage, and if that vintage will fit my ‘05.
 
The first rebuilt one was sent with a bad main bearing and I was forced to use it for a few months because they were insistent that it was only making noise because “the gears need breaking in”. The replacement was fine for 9 months and then started kicking out of reverse. These units were billed as “having all new gears” and having replaced “problematic 1st and reverse gears”.
 
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My vote is just swap to the ax15..im not a nsg370 hater either but I haven't had the best of luck. I had one rebuilt by a well known transmission shop and while the reverse problem was fixed it now ground going into second unless you shifted really slow...the right thing to do is make them fix it but the jeep was my daily driver...in the end with the cost of rebuilding the nsg370 I'm fairly certain I was close to a new ax15 and would have only needed the expensive bellhousing. The clutch gets replaced either way. Just my .02
 
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My vote is just swap to the ax15..im not a nsg370 hater either but I haven't had the best of luck. I had one rebuilt by a well known transmission shop and while the reverse problem was fixed it now ground going into second unless you shifted really slow...the right thing to do is make them fix it but the jeep was my daily driver...in the end with the cost of rebuilding the nsg370 I'm fairly certain I was close to a new ax15 and would have only needed the expensive bellhousing. The clutch gets replaced either way. Just my .02
The cure seems to be worse than the disease when people “fix” the NSG 370. I am very irritated though that I will be under geared just from having to switch the transmission. I was not ready to do a re-gear.
 
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