Howdy, new member here, finally got my own TJ, a 2001 4.0 Sport in good shape overall, except for the trans grinding badly in every gear (even when double-clutched). I've read that rebuilt NV3550s are a crapshoot since NV is out of business and aftermarket parts are questionable. I saw Novak's ax15 kit but they said they're out of the remans and the new ax15 that fits the 2001s are a little pricey for me right now. Anyone have any leads on where to get a reman ax15 that bolts into a 2001? We just moved, and I just ordered lots of parts for my daily driver truck so trying to save as much as feasible on a replacement trans. BUT I definitely would prefer upgrading to an AX15 as I plan on my TJ becoming my daily as it gets better mileage than my truck (believe it or not). Any info or leads would be greatly appreciated, thank y'all!
2001 with NV3550 (well, most of it)
- Thread starter El_Gato
- Start date
Are you sure it's the transmission? If it's grinding in every gear could it be your clutch instead?
It's not the "best" solution but you could pick up a AX15 used to get you going if you determine 100% it's the transmission and not the clutch. One place to look is on Car-Part.com and search for a transmission near you. Or search for a Jeep dismantler and buy a transmission from them.
Pretty sure, it doesn't grind going into 1st and supposedly the clutch is newer (pedal feels great and it engages very smoothly and grabs fast, so I believe it). I'm gonna replace the hydraulics anyways, but with the 217k miles it has, and the fact that it feels like the problem is worn synchros, I'd bet the trans itself is the culprit. Car-part is a bust, everything is over $1500 for used high mileage or reman NV3550s. And my understanding is an AX15 out of say a 99 isn't a direct swap but I don't know what all I'd have to change over. So the best option I've found is the Novak conversion AX15. BUT as I said, since they only have new I wanted to see if there was other avenues to get a converted ax15. Or a parts list so I can bolt in a used ax15 from an earlier 4.0 TJ would be awesome too!
Advance Adapter has new AX15 transmissions. I thought they had a conversion kit also but am not finding it yet.
https://www.advanceadapters.com/transmission-ax15-4wd-new-unit-750-tip-boxed
Look here: https://wranglertjforum.com/threads/nv3550-to-ax15-transmission-swap.43780/
Edit: From that thread I linked there isn't a lot to swap to a AX15. That is what I was meaning as in using a used AX15 if you can't afford a new AX15 right now.
https://www.advanceadapters.com/transmission-ax15-4wd-new-unit-750-tip-boxed
Look here: https://wranglertjforum.com/threads/nv3550-to-ax15-transmission-swap.43780/
Edit: From that thread I linked there isn't a lot to swap to a AX15. That is what I was meaning as in using a used AX15 if you can't afford a new AX15 right now.
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I am in the middle of swapping an AX15 in.. the NV3550 shit the bed.
You can find the NV3550, but they cost more than the AX and from all counts are not worth it.
I purchased a new AX15 from Novak. Along with the reverse light pig tail (sensor is on the opposite side of the box) and an adjustable transmission mount. They were a joy to deal with and the new gear box arrived four days earlier than expected. It wasn't the cheapest option but I don't want surprises or worries.
Update: Turns out Novak offers a 5% discount for forum members.
The swap seems very popular and every shop I spoke to said something like.. yeah.. we do it all the time. Bell housing mates right up. So does the NP231. A transfer case cable shifter is recommended, and I had it already. Unsure about the transmission mount which may or may not be compatible, so I bought the Novak Adjustable. I'll return it if not needed. I also added a B&M Short Throw Shifter since I had one on the NV3550 that I loved but wasn't compatible with the AX.
The NV3550 to AX15 Swap thread
Alternatives...
You can find the NV3550, but they cost more than the AX and from all counts are not worth it.
I purchased a new AX15 from Novak. Along with the reverse light pig tail (sensor is on the opposite side of the box) and an adjustable transmission mount. They were a joy to deal with and the new gear box arrived four days earlier than expected. It wasn't the cheapest option but I don't want surprises or worries.
Update: Turns out Novak offers a 5% discount for forum members.
The swap seems very popular and every shop I spoke to said something like.. yeah.. we do it all the time. Bell housing mates right up. So does the NP231. A transfer case cable shifter is recommended, and I had it already. Unsure about the transmission mount which may or may not be compatible, so I bought the Novak Adjustable. I'll return it if not needed. I also added a B&M Short Throw Shifter since I had one on the NV3550 that I loved but wasn't compatible with the AX.
The NV3550 to AX15 Swap thread
Alternatives...
- Summit Racing sells a remanufactured Zumbrota NV3550
- Summit also sells the AX15.. both new and rebuilt I believe.
- Rockland Standard Gear sells a "beefed up" Nv3550 called the Terminator or Tranzilla. I understand it is actually an AX15. They are out of stock until after the new year.
- Powetrain Products sells rebuilt NV3550. I think they had AX15s too
- Extreme Performance lists another "beefed Up" NV3550 called the XP1. No stock when I called them
- Advanced Adapters referred me to Summit as they had no inventory
- DeadJeep had used gear boxes but I wasn't going to buy someone else's problem.
- USA Parts online had one of each of the AX & NV when I called them, but it's hit or miss
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MikekiM is correct, AA never offered an adapter for the AX15 into newer 6 cyl TJ,s. I was getting it confused with the kit for the AX15 behind a 4 cyl 2.5.
I think you've got enough info to make an informed decision on doing a AX15 swap.
I think you've got enough info to make an informed decision on doing a AX15 swap.
Wow, thank you so much for all of this info!!!! I really appreciate you sharing it with me, definitely gives me plenty to look into. And I 100% agree with your sentiment on tossing in a used NV3550, I plan on keeping my TJ for a while so AX15 definitely seems the way to go.
Indeed, definitely swapping to an AX15 and thanks to MikekiM I have plenty of resources to check to find mine! I can't wait to get my TJ on the road....then off of it lol. Been wanting something to do light off-roading in for years, and I'm soo happy it ended up being a TJ. It reminds me of my younger days.
Thanks all, hoping to post an update here soon once it's fixed! I'm also thinking I may try to repaint the front end myself, it's only the hood, fenders, and windshield frame that are faded so I think it could be doable in the garage.
Someone buy something from Novak and use my 5% discount!
Bummed neither I or sales knew about it when I ordered. Would have saved me a chunk of change.
Hey now, that sounds like a plan! Thank you so much! Will definitely reach out when I'm ready to buy soon!
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