Novak bellhousing for converting 05-06 NSG370 to AX15

[lbrooksnm]

I have pretty much decided to go from an NSG370 to an AX15 in my 2005 TJ Unlimited. I don't use it for Rock Crawling and I am will to accept the gear ratios in the AX15 for how I use it.

I have emailed both Advanced Adapter and Novak about cost and compatibility. For the cost I have from each of them, Novak comes out about $450 less expensive. I have found a number of post on the web that have used the Advanced Adapter bellhousing/transmission. To use the Advanced Adapters will cost me ~$2750, at the price, I would probably take my chances on a rebuilt NSG370 or buy the tools and rebuild my own.

I have not been able to find any post on the web from someone who has used the Novak bellhousing in an '05-'06.

There is some conflicting information on their website about whether it will work on the '05 and '06s. It seems like they may have updated the product but not updated all of their website information.

https://www.novak-adapt.com/catalog/adapters/engine-to-transmission/amc/ax15-to-nv3550-amc/
When I emailed them they said that it will support both CPS locations. I did not get a definite answer in the email on whether or not the slave cylinder from the NSG370 could be reused.

So here is my question:
Has anyone used the Novak Kit 52107552-K, Bellhousing, 4.0L to AX15 & NV3550 to convert a 2005 or 2006 from an NSG370 to an AX15? How did it go?

 

[freedom_in_4low]

Bumping for you because I am also interested in this swap as reverse is almost no longer usable on the trail.

I'm aware of the bellhousing and what not... What else is required? Will a 97-99 boot fit a 2006 tub, do we need an Ax15 mount bracket or will the nsg370 bracket work? If we need the Ax15 bracket, will it mount to the 03-06 skid/crossmember?

 

[lbrooksnm]

I talked to Novak again and they assured be it would work fine and a number of people have used this bellhousing for what I am planning. I placed the order on 3/15/22 and received parts in three days, except for the bellhousing. I have not started work since the bell housing is out of stock, they told me it would be back in stock in 3 to 4 weeks.

This is what Novak said I would need:

1. Kit 52107552-K, Bellhousing, 4.0L to AX15 & NV3550, 93-04 w/ CPS in 10 loc., external slave. New aftermarket, enhanced casting, early/late CPS prov, clutch release pivot ball, spring clip

2. TR-AX14, Transmission assembly, TurnKey, AX15 manual. New with all available updates and enhancements

3. PB-2001157, Bearing, pilot, Jeep 4.0L (92-06), Mopar 5.2L engines to Jeep T14 (72-15), T15, T18 (1972-1975), AX1

4. RMAX15, Kit RMAX15, mount, rear, AX15 and NV3550 transmissions, universal 1.00 kit universal & adjustable

They did think I would be able to use the clutch slave cylinder - "The slave cylinder off of your NSG370 should work, but if it doesn't you could get one for an earlier TJ." I will likely put a new clutch in while I am there.

I have looked at some online information on the shift boot, I going to figure this out when I get there.

If you like I will let you know how thinks go and what all parts I ends up using. I need to do this soon, I can barely use reverse at all anymore.

 

[mrblaine]

I have pretty much decided to go from an NSG370 to an AX15 in my 2005 TJ Unlimited. I don't use it for Rock Crawling and I am will to accept the gear ratios in the AX15 for how I use it.

I have emailed both Advanced Adapter and Novak about cost and compatibility. For the cost I have from each of them, Novak comes out about $450 less expensive. I have found a number of post on the web that have used the Advanced Adapter bellhousing/transmission. To use the Advanced Adapters will cost me ~$2750, at the price, I would probably take my chances on a rebuilt NSG370 or buy the tools and rebuild my own.

I have not been able to find any post on the web from someone who has used the Novak bellhousing in an '05-'06.

There is some conflicting information on their website about whether it will work on the '05 and '06s. It seems like they may have updated the product but not updated all of their website information.

https://www.novak-adapt.com/catalog/adapters/engine-to-transmission/amc/ax15-to-nv3550-amc/
When I emailed them they said that it will support both CPS locations. I did not get a definite answer in the email on whether or not the slave cylinder from the NSG370 could be reused.

So here is my question:
Has anyone used the Novak Kit 52107552-K, Bellhousing, 4.0L to AX15 & NV3550 to convert a 2005 or 2006 from an NSG370 to an AX15? How did it go?

What is the break down on the price from AA?

I've used the one from AA before and I don't recall it being a 2700 dollar endeavor unless you are counting the cost of the trans.

 

[lbrooksnm]

I am including the cost of the transmission. AA and Novak are pretty close on that. In round numbers here is what I was looking at based on what AA said I needed and what Novak said I needed. It remains to be seen how much it costs in the end.

Advanced Adapter (from shopping cart):
712590L bellhousing $520
716340 slave cylinder $195
26-AX15 $1660
Shifter $26
Tax $206
Shipping $163

Total $2770

Novak:
Bellhousing $369
AX-15 w/shifter. $1690
Adjustable Mount. $92
Pilot Bearing $13
Tax $0
Shipping $110

Total $ 2274 (from receipt)

 

[freedom_in_4low]

Not really apples to apples since the components list isn't the same, but the difference looks to be in the bellhousing itself and the lack of taxes on Novak. Wonder how Novak gets away without charging sales tax and what makes AAs bellhousing so much pricier.

 

[mrblaine]

Not really apples to apples since the components list isn't the same, but the difference looks to be in the bellhousing itself and the lack of taxes on Novak. Wonder how Novak gets away without charging sales tax and what makes AAs bellhousing so much pricier.

When we got the AA bellhousing, the kit included a new all metal throw-out bearing, ball and clip for the clutch fork, and quite a few other odds and ends that were surprising in quantity and quality. I remember thinking if you had the trans, you wouldn't need much else to do the swap.

Edit- I checked the parts list. Clutch fork, hardware, pivot ball, throw-out bearing, pilot bearing and bushing for the end of the crank.

 

[freedom_in_4low]

When we got the AA bellhousing, the kit included a new all metal throw-out bearing, ball and clip for the clutch fork, and quite a few other odds and ends that were surprising in quantity and quality. I remember thinking if you had the trans, you wouldn't need much else to do the swap.

Edit- I checked the parts list. Clutch fork, hardware, pivot ball, throw-out bearing, pilot bearing and bushing for the end of the crank.

The throw out bearing is worth something to me for sure, since I don't plan to put it all back together with any used clutch components.

What have you had to do vis-a-vis the mount bracket? Can you use a nsg mount and 03-06 skid with an Ax15? Or do you have to use the Ax15 mount (which is known to interfere with a 241, which may crawl higher on my potential future upgrade list with the loss of the nsg 4.46 1st gear), or is it some union of the two? I tend to distrust Novak because of how wrong they've steered me in the past when it comes to TC input gear lengths and I don't like that they said one was needed but AA didn't seem to. I don't like that novar just phones it in with some "universal adjustable" mount that replaces the factory mount with some rubber bushings that I don't know how well they isolate.

Rockauto shows different slaves for 05-06 but Novak didn't sell the OP a new one and AA was noncommittal. I'll be interested in how that comes out.

I'll probably end up calling AA tomorrow. Anybody got a discount code? Haha

 

[mrblaine]

The throw out bearing is worth something to me for sure, since I don't plan to put it all back together with any used clutch components.

What have you had to do vis-a-vis the mount bracket? Can you use a nsg mount and 03-06 skid with an Ax15? Or do you have to use the Ax15 mount (which is known to interfere with a 241, which may crawl higher on my potential future upgrade list with the loss of the nsg 4.46 1st gear), or is it some union of the two? I tend to distrust Novak because of how wrong they've steered me in the past when it comes to TC input gear lengths and I don't like that they said one was needed but AA didn't seem to. I don't like that novar just phones it in with some "universal adjustable" mount that replaces the factory mount with some rubber bushings that I don't know how well they isolate.

Rockauto shows different slaves for 05-06 but Novak didn't sell the OP a new one and AA was noncommittal. I'll be interested in how that comes out.

I'll probably end up calling AA tomorrow. Anybody got a discount code? Haha

We put it in an 05 that was running an Atlas so we already had a custom crossmember in the rig. Not sure what would have to be done on a fresh install.

 

[machoheadgames]

The throw out bearing is worth something to me for sure, since I don't plan to put it all back together with any used clutch components.

What have you had to do vis-a-vis the mount bracket? Can you use a nsg mount and 03-06 skid with an Ax15? Or do you have to use the Ax15 mount (which is known to interfere with a 241, which may crawl higher on my potential future upgrade list with the loss of the nsg 4.46 1st gear), or is it some union of the two? I tend to distrust Novak because of how wrong they've steered me in the past when it comes to TC input gear lengths and I don't like that they said one was needed but AA didn't seem to. I don't like that novar just phones it in with some "universal adjustable" mount that replaces the factory mount with some rubber bushings that I don't know how well they isolate.

Rockauto shows different slaves for 05-06 but Novak didn't sell the OP a new one and AA was noncommittal. I'll be interested in how that comes out.

I'll probably end up calling AA tomorrow. Anybody got a discount code? Haha

Watching embark with mark’s video, the NSG 4-bolt trans mount bracket that the trans mount bolts to bolted straight onto the AX15. The only problem is the AX15 has some bolts on the bottom of
The case that protrude ever so slightly into the overlapping area of the trans mount bracket, so he had to notch the bracket slightly for those two bolt heads.

The slave/master is the same on all models. It’s the same part number across every year, only differences being the letter designations at the end of the part number. So those would be minor revisions over the years (I don’t know what the revisions are) but the part number being the same means it’s essentially the same part. Somewhere around 05-06 there became a recall on the master cyl for the clutch safety switch no longer working and allowing the Jeep to start without depressing the clutch.

There is no reason your slave wouldn’t work. The bellhousings from AX to NV to NSG are all essentially the same using the same fork, pivot ball, pivot ball clip, clutch, TOB, and pilot bearing.

I don’t know what issues if any there would be with a 241. I don’t see why there would be issues? But you’d have to look into that, because I can’t confirm for sure.

As for Novak and being incorrect, they technically aren’t incorrect in some of the things people say they are “wrong” about. A lot of the confusion comes from input gears like you said. For example, Novak will say an AX15 needs the short input gear. Then folks on here with a 99 AX15 will jump in and say theirs had a long input gear. Well, Novak said the AX15 requires a short, so who is right? Well, technically the AX15 only requires a minimum of a short gear. The longer gear will fit fine and not bottom out on anything. So where Novak says a long gear can cause problems, they are incorrect. But basically the AX15 can get by with a short or long input gear just fine. Just because some members’ 99s had long gears, doesn’t mean that was needed for their AX15. That would be a case of laziness/consolidating the parts lineup. Why they didn’t do it earlier? Who knows. Basically, Novak lists most of the typical setups, but there are a few different setups than they list in the real world that still work fine. So while people find something different than Novak says they should have, Novak technically isn’t completely wrong. So basically, don’t worry about input gears.

Where problems WOULD come up, would be if you were installing a short gear transfer case onto a 32RH. The 32 needs the long gear or at the bare minimum, that fancy Teraflex extended seal that can reach out and seal to a short gear. Otherwise you will piss out fluid as soon as you cranked it up.

I would buy whatever bellhousing supports the 5:00 CKP sensor location, and I would (and did) buy a trans from Novak for cheaper no-tax and better shipping costs. The difference for me to buy from AA would be like $180 last I checked.

 

[freedom_in_4low]

Watching embark with mark’s video, the NSG 4-bolt trans mount bracket that the trans mount bolts to bolted straight onto the AX15. The only problem is the AX15 has some bolts on the bottom of
The case that protrude ever so slightly into the overlapping area of the trans mount bracket, so he had to notch the bracket slightly for those two bolt heads.

The slave/master is the same on all models. It’s the same part number across every year, only differences being the letter designations at the end of the part number. So those would be minor revisions over the years (I don’t know what the revisions are) but the part number being the same means it’s essentially the same part. Somewhere around 05-06 there became a recall on the master cyl for the clutch safety switch no longer working and allowing the Jeep to start in gear.

There is no reason your slave wouldn’t work. The bellhousings from AX to NV to NSG are all essentially the same using the same fork, pivot ball, pivot ball clip, clutch, TOB, and pilot bearing.

I don’t know what issues if any there would be with a 241. I don’t see why there would be issues? But you’d have to look into that, because I can’t confirm for sure.

As for Novak and being incorrect, they technically aren’t incorrect in some of the things people say they are “wrong” about. A lot of the confusion comes from input gears like you said. For example, Novak will say an AX15 needs the short input gear. Then folks on here with a 99 AX15 will jump in and say theirs had a long input gear. Well, Novak said the AX15 requires a short, so who is right? Well, technically the AX15 only requires a minimum of a short gear. The longer gear will fit fine and not bottom out on anything. So where Novak says a long gear can cause problems, they are incorrect. But basically the AX15 can get by with a short or long input gear just fine. Basically, Novak lists most of the typical setups, but there are a few different setups than they list in the real world that still work fine. So while people find something different than Novak says they should have, Novak technically isn’t completely wrong. So basically, don’t worry about input gears.

I would buy whatever bellhousing supports the 5:00 CKP sensor location, and I would (and did) buy a trans from Novak for cheaper no-tax and better shipping costs. The difference for me to buy from AA would be like $180 last I checked.

Awesome info! I have no issue notching the mount bracket and I love this idea even more if I don't even have to bleed the clutch.

My concern about the 241 had to do with another post I saw of someone swapping one into their early TJ, and the early mount hit the TC before reaching the transmission. I shouldn't have that problem since I suspect they used one mount for the nsg370 whether it had 231 or 241. Will check the parts manual to make sure though.

Your comments on Novar make some sense, but I wish they'd just present it that way; it would be much more simple and probably avoid a few unnecessary input gear changes. Manuals can take either one, 42RLE needs a short and 32RH needs long unless you buy a seal extension. That's literally all there is to it.

The 231 in my LJ actually came out of my 99 TJ, has a long input and came on an Ax15 so I already know it's good to go.

 

[machoheadgames]

Awesome info! I have no issue notching the mount bracket and I love this idea even more if I don't even have to bleed the clutch.

My concern about the 241 had to do with another post I saw of someone swapping one into their early TJ, and the early mount hit the TC before reaching the transmission. I shouldn't have that problem since I suspect they used one mount for the nsg370 whether it had 231 or 241. Will check the parts manual to make sure though.

Your comments on Novar make some sense, but I wish they'd just present it that way; it would be much more simple and probably avoid a few unnecessary input gear changes. Manuals can take either one, 42RLE needs a short and 32RH needs long unless you buy a seal extension. That's literally all there is to it.

The 231 in my LJ actually came out of my 99 TJ, has a long input and came on an Ax15 so I already know it's good to go.

yeah maybe an issue on the early mounts. Really not sure there. I would expect they changed the mount in 2000 but I too would have to check the parts manual. I would estimate you have a really strong chance of having the right bracket for a 241 being that you have a transmission a rubi could have come with. Knowing how Jeep is, I highly doubt they would have had two different mounts per tcase. But, the manual will clear that up nicely.

Yeah I agree, Novak is not perfect and ideally needs to clean up their crap too. Without looking I forget what they say but something about damage in the AX15 if used with a long input gear. They should prove that to themselves before telling the whole world they need to change their long gear. It’s pretty obvious the 99’s have proven that wrong time and time again and we all know Jeep didn’t create a special AX15 for 1999 specifically to accept a long gear. It would certainly be ideal for them to update their website to reflect what years of findings have found: basically exactly what you just summarized. Similar to this, Novak after tons of recommendations to fix their shifter, didn’t really ever fix it either. Despite their flaws though, they were a good company to buy a transmission from with considerable savings over AA. So I definitely recommend them for that. I know they sell bellhousings too but I’m not sure if theirs has the 5:00 sensor spot, so maybe AA is the best bet for that.

I think you will like the AX15. I know you love your first gear, and maybe you’ll miss that, but I find the AX15 to have nice gearing overall on the street. I will say you’d probably wish you had done 5.13 for the 35’s, but it is what it is. The biggest flaw to the AX in my mind (and any 5 speed) is that 3rd bridges the gap from a 2.X 2nd to the 1:1. The majority of 6 speeds, NSG included, have 3&4 splitting that gap and it’s super nice. So you might miss that. However, for a smooth shifting, strong transmission, hard to beat the AX.

If I were building my perfect transmission, it would be a 6 speed, NV 4:1 1st, NSG 2-5, and AX 5th (0.79) as 6th. Granny or as low as possible reverse. It would shift with the smoothness of an AX. But, we can’t all get what we want sadly.

 

[mrblaine]

If I were building my perfect transmission, it would be a 6 speed auto with a .80 overdrive.

FIFY

 

[machoheadgames]

FIFY

That might be your perfect trans, but for me and what I like, it would be manual. I’m not a hard wheeler.

I agree the gearing I listed would be good on either type of trans though.

 

[rockin05tju]

What is the cost for a complete nsg370 rebuild? I read that one of the shafts needs completely replaced to get rid of the rattle sound? Plus a new shift tower (boot leaks, unavailable seperately), fork assembly, gears...etc

 

[rockin05tju]

.

 

[freedom_in_4low]

I think you will like the AX15. I know you love your first gear, and maybe you’ll miss that, but I find the AX15 to have nice gearing overall on the street. I will say you’d probably wish you had done 5.13 for the 35’s, but it is what it is. The biggest flaw to the add in my mind (and any 5 speed) is that 3rd bridges the gap from a 2.X 2nd to a 1:1. The majority of 6 speeds, nsg included, have 3&4 splitting that gap and it’s super nice. So you might miss that. However, for a smooth shifting, strong transmission, hard to beat the AX.

For about a month last year I had my 99 TJ AX15 with 31s and 3.73 and my 06 LJ NSG with 32s and 4.88 (which was overgeared at that point). I remember noticing how nice the Ax15 shifted and liking the spacing between the ratios, but how awesomely slow the NSG would crawl. Some of that gap obviously closed going to 35s but it's still the right speed for me and it's the one thing that's kept me from jumping into this swap with both feet. Though when I think about it in terms of percentages, I don't know if I'll really notice... Like, can I tell the difference idling in 4L, between 1.45ft/s and 1.66ft/s?

On the other end, I drove the LJ 250 miles today and I think I'll be ok with my 4.88s...a lot of our interstates are 75-80mph so I'd be cruising at 2850 instead of 3000 and that should be ok for the foreseeable future (building a house, not likely to move back to the mountains any time soon).

If I were building my perfect transmission, it would be a 6 speed, NV 4:1 1st, NSG 2-5, and AX 5th (0.79) as 6th. Granny or as low as possible reverse. It would shift with the smoothness of an AX. But, we can’t all get what we want sadly.

We have similar tastes. You bring up a good point with the NV. High Impact sells a rebuilt NV3550 for $1350 + $350 core, so in the ballpark of a new AX15. All this swap stuff would apply to the NV as well and I would at least have a 4:1 1st. I have no experience with the NV3550 though, so I don't know what might make it less desirable than the AX, other than that the AX is still being made new.

 

[mrblaine]

I have no experience with the NV3550 though, so I don't know what might make it less desirable than the AX, other than that the AX is still being made new.

I think it depends on what you read on the internet on any given day. I've had folks do the swaps in place of both for the other one several times based on some bull that convinced them their perfectly working AX or NV was a piece of poo.

 

[machoheadgames]

For about a month last year I had my 99 TJ AX15 with 31s and 3.73 and my 06 LJ NSG with 32s and 4.88 (which was overgeared at that point). I remember noticing how nice the Ax15 shifted and liking the spacing between the ratios, but how awesomely slow the NSG would crawl. Some of that gap obviously closed going to 35s but it's still the right speed for me and it's the one thing that's kept me from jumping into this swap with both feet. Though when I think about it in terms of percentages, I don't know if I'll really notice... Like, can I tell the difference idling in 4L, between 1.45ft/s and 1.66ft/s?

On the other end, I drove the LJ 250 miles today and I think I'll be ok with my 4.88s...a lot of our interstates are 75-80mph so I'd be cruising at 2850 instead of 3000 and that should be ok for the foreseeable future (building a house, not likely to move back to the mountains any time soon).

Honestly on the crawling I doubt you will notice much difference. I think you will feel it more on the street than anything, being able to stretch 1st a bit longer, which I like. Obviously offroad 1st in the NSG would be better for crawling but I don't know that it will really make all that much difference real world. Of course, if you had 5.13 with the AX, then that would help get you back closer to what you have now. But obviously that isn't worth a regear alone, better off changing the tcase for that.

Yeah you'll be fine...4.88 isn't bad with 35's either. It will need a bit more downshifting sometimes but not terrible.

Really what I like about a 6 speed is you have more usable ratios for times like passing. 3rd in a 5 speed is traditionally pretty low so that it's not too far away from 2nd. Problem is, with a regeared Jeep that 3rd gear becomes less usable on the highway for passing. My numbers tell me you'll max out 3rd at around 75 with the 5 speed, which isn't bad, but it means if you wanted to quickly overtake someone, you will need to rev match way up there to get into 3rd and then have to basically take it to redline if you are passing 70-80ish and going around someone at a similar speed. Since you will redline before getting to 80, you'd need to go to 4th which kind of sucks.

On the contrary, the 6 speed has that perfect split between 3 and 4, that you can use 3rd for really good mid range acceleration, and 4th can be that passing gear at the 70-80 range. 4th on the 6 speed wouldn't max out until like 85 on the same tire/gear combo. Really it's all compromises. Real world, the AX is a very good transmission. There are very few times I find myself needing to wind out 3rd for a super hard pass. So it's not really a problem, but on paper the 6 speed is just better at covering all the different scenarios.

We have similar tastes. You bring up a good point with the NV. High Impact sells a rebuilt NV3550 for $1350 + $350 core, so in the ballpark of a new AX15. All this swap stuff would apply to the NV as well and I would at least have a 4:1 1st. I have no experience with the NV3550 though, so I don't know what might make it less desirable than the AX, other than that the AX is still being made new.

I'd stick with the AX. If I bought an NV Jeep I wouldn't rush to swap it out, but I'd rather have the AX. The new aspect is really nice, the NVs are loud, don't shift as smoothly, and real world I don't think the 4:1 first is that far away from the 3.83 AX15. the 3.5:1 reverse is definitely not ideal. The other two are in the 4's. They both work fine overall, but in your situation I don't see a good reason to choose the NV when coming from the NSG.

 

[machoheadgames]

I think it depends on what you read on the internet on any given day. I've had folks do the swaps in place of both for the other one several times based on some bull that convinced them their perfectly working AX or NV was a piece of poo.

I agree. Neither are perfect and neither are terrible. NV slightly better ratios except reverse, AX is overall shifts a bit more smoothly and is quieter. Personally given the choice I'd choose the AX simply because it can still be found new and is overall more quiet. Either will get the job done.