Gen III Hemi Swap into TJ Reference Guide & Swap Info

I'm not knocking it as a viable transmission but just trying to put the info out there as a warning. Depending on the amount of lift you are shooting for you could negate the needed belly skid drop. I'm just glad there are companies out there offering stuff for us.

I talked to one guy who put a NV4500 into his TJ and he redid his trans tunnel to make it fit instead of dropping it down.

Oh I didn’t think you were knocking it at all - I took it (and I hope others do as well) as additive to part of the total “information package” :)

I think a huge advantage to a forum such as this is the collective information pool that the members bring, as well as the ability to easily find/reference and discuss options over the other.

Plus I’ve got no skin in the game for this swap - I can’t wait to get back to wheeling an auto 😂
 
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Oh I didn’t think you were knocking it at all - I took it (and I hope others do as well) as additive to part of the total “information package” :)

I think a huge advantage to a forum such as this is the collective information pool that the members bring, as well as the ability to easily find/reference and discuss options over the other.

Plus I’ve got no skin in the game for this swap - I can’t wait to get back to wheeling an auto 😂

Some have gotten touchy before.
I would like to see someone offer a transmission that would handle the torque of a Hemi or LS for those who still want a manual transmission.
But on the same note it's one of the reasons Ram no longer offers a manual transmission with a diesel. 2018 was the last year and if you wanted a manual behind the 6.7 you took it as a detuned engine. I had a 2008 Ram 3500 with the 6 speed manual and smoked the stock clutch in under 10K miles. And I hadn't done any internal work to it. All I'd done was to remove the emissions and put a 5" exhaust on it. Plus a tuner & that was it. Had to install a dual disc clutch and then the transmission blew with about 35K miles on it. I love rowing gears it just isn't a option for me anymore.

And yes I would like to put together a thread for people doing a Magnum V-8 swap. I've found a lot of information and have a lot of it listed in my thread but you have to search thru it to find. But when people have posted on here asking questions about this swap have tried to share what I know. My hard part is I let someone else do the first swap for me so there were some things I can't answer.
 
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The R154 is close to the AX15 and shares lots of parts, but note that while the R154 was indeed used behind the Supra, those that built up their 2ZJ's often found the manual trans to be the weak spot in the drivetrain and most running seriously boosted engines all went with an automatic (or in some instances modified a Tremec to fit).

Personally, I don't think I'd ever consider an AX15 a viable candidate in stock form. RSG does makes an upgraded "Terminator" AX15 that uses some upgraded gears and internals of the later Supra R154 transmissions. Supposedly, it is typically quite reliable behind LS-powered Jeeps. The NV4500 is another option, though in my opinion the NV is a big ol' thing and since it has been out of production since the mid-2000's, it is getting harder to find. It's often too long for non-stretched Jeeps too!

The one option that I'd be most inclined to try out is the new(ish) Tremec TR-4050. https://tremec-blog.com/tremec-tr-4050-off-road-manual-transmission-solution/

It has an excellent set of gear ratios: 6.16, 3.11, 1.71, 1.00, 0.76 which would work well on the street and trail. That 6.16 first gear with a 2.72 t-case Lo range, and 5.13 axle ratio would yield a ~86:1 crawl ratio - that is higher than an 5-speed TJ Rubi. If you were to couple the SST with a Rubicon t-case, you would end up with a 126:1 crawl ratio - enough to make even the double/triple t-cased Toyota guys jealous! :)
100% appreciated. Ill look more into the Tremec because that granny gear is appealing but one of the main reasons I want to find a way to hold onto the AX-15 is the fitment with a tummy tuck. And no I wouldn't dare consider a stock AX-15 either. However I should qualify when I say I'm shooting for a transmission that can handle 400+ lb-ft. I mean like just around 400-420 lb-ft of torque. Other than a port and polish and custom tuning (~400 HP), I wont be doing any major horsepower mods to the Hemi, I'd rather just build a go-fast car for serious HP. I had heard of the RSG Heavy Duty AX-15 but is it in production? I can only see their Terminator NVG3550.
 
100% appreciated. Ill look more into the Tremec because that granny gear is appealing but one of the main reasons I want to find a way to hold onto the AX-15 is the fitment with a tummy tuck. And no I wouldn't dare consider a stock AX-15 either. However I should qualify when I say I'm shooting for a transmission that can handle 400+ lb-ft. I mean like just around 400-420 lb-ft of torque. Other than a port and polish and custom tuning (~400 HP), I wont be doing any major horsepower mods to the Hemi, I'd rather just build a go-fast car for serious HP. I had heard of the RSG Heavy Duty AX-15 but is it in production? I can only see their Terminator NVG3550.

Have you look at this? You mention it in your post.

Terminator™ - Rockland Standard Gear, Inc. (rsgear.com)

But they don't offer any info as to what type of power it can handle.
 
Have you look at this? You mention it in your post.

Terminator™ - Rockland Standard Gear, Inc. (rsgear.com)

But they don't offer any info as to what type of power it can handle.
Rick from RSG many years ago allegedly “confirmed” 385 ft-lbs (which is close to what the R154t was rated to)...

It’s all internet folklore however and RSG’s website hasn’t been updated since what appears to be the Clinton Administration. A bud of mine called a few years ago and the lady that answered was less than helpful and unable to confirm anything.
 
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I have looked at that, the info on the page is kinda sparse but from what I surmised its an upgraded NVG3550, unless that is actually an upgraded AX-15 and they just dont actually say it.
Yeah their website is horrible... says copyright 1992, which I think was the last time someone updated it or designed a graphic for it. The Terminator is an AX-15 replacement for the NV3550 (also an older, worn AX-15 of course).

After doing some digging, I had originally believed that the RSG "Terminator" was an upgraded AX-15. It is, in a way since it uses some of the R154 internals and gear sets, but it isn't something specific to the RSG offering. This is the same trans you can buy directly from Novak and others. They have the same torque capacity and internal upgrades as these now come this way directly from Aisin.
 
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Got lucky on a Marketplace find:

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I did some exploratory work - this time focusing on the P/S setup. I see a lot of conflicting info on the P/S options, compatibilities, etc., so I won't be confident with a solution without some experimenting.

The factory Hemi PS pump has the same mounting hole spacing at the PSC CBR pump, which is the same as the older Jeep 4.0L pumps. Like the factory pump, all three holes are through-holes. The PSC pump also has 3 holes, but the one on the left (when looking at it from the front) is a blind-hole.

Spacing wise, the pulleys are in very similar locations - only ~1/8" off:
IMG_1797.JPG

[Factory 2012 5.7L Hemi pulley - showing distance to the flat cover behind the pump]

IMG_1802.JPG

[CBR pump as provided in PSC's #1852 kit]

It appears as though PSC offers a few pump options for the JK, including what appears to be a CBR pump with a few spacers. The PSC rep I spoke with confirmed that the JK pump kit uses the same pump but with a different size pulley. He also confirmed that the JK-Hemi kits only utilize the top and bottom bolts. I placed an order for some spacers, a new 3/4" return line, and a 180º fitting.

Fingers crossed that this is an easy solution :)
 
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When I did the Hemi, at first I tried using the stock pump to run the hydro assist and hydro boost. No dice. Too slow, and overheated. Went to the PSC remote reservoir pump, and it works like a charm. No spacers needed as I recall.
 
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When I did the Hemi, at first I tried using the stock pump to run the hydro assist and hydro boost. No dice. Too slow, and overheated. Went to the PSC remote reservoir pump, and it works like a charm. No spacers needed as I recall.
It's weird - the early year pumps were too weak and the later year pumps are too much. A lot of people have tried the later-year truck pumps and they have too much juice and end up blowing the seals out of steering gears!

What pump did you end up going with, the CBR? I know there are some differences between the Eagle and non-Eagle accessories. The guys at PSC said "you will need 2-3 spacers" and he even went in the back to grab and measure the thickness (they are confirmed 3/16" thick). Mine shows to be ~1/8" offset. I figured I can use a flat sander and get my spacer down to the 1/8" needed rather easily.

Here's the PK1860/62 kit that PSC sells. You can see the two spacers they include with their setup. It possible that they sell a different pulley with a different offset (it wasn't mentioned to me)???
pk1860_1_of_1_.jpg
 
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Unfortunately the TeraFlex 4877480 TJ gas pedal bracket kit isn't going to work...

IMG_1815.JPG

First, the spacing on the later-model pedals is indeed not the same as the earlier pedals.

63476380769__8AACF3B1-4C19-4ECC-AA8C-BCA6155316F7.JPG

Second, the holes weren't drilled on the proper side! Based on where the angled-side of the bracket is, plus the holes being in the wrong orientation, I'm beginning to suspect that the bracket was pre-drilled and then put into the forming brake on the wrong side...

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On a happy note, the Hemi NGC mounts in the same spot with the same hardware as the 4.0L JTEC :)

IMG_1813.webp
 
For a guy in the planning stages of a swap, do you think it would be better to buy a whole truck, or just piece together what you need? Wheeling in the sand and mud, I need some horsepower... The 4.slow isn't the right engine. I can't get to it for at least a year, but I might start accumulating parts...

By the way, before this thread, I was leaning LS. This thread has me convinced that the hemi is now the way to go. Really nice work, so far.
 
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For a guy in the planning stages of a swap, do you think it would be better to buy a whole truck, or just piece together what you need? Wheeling in the sand and mud, I need some horsepower... The 4.slow isn't the right engine. I can't get to it for at least a year, but I might start accumulating parts...

By the way, before this thread, I was leaning LS. This thread has me convinced that the hemi is now the way to go. Really nice work, so far.

Mike,
It's always better to buy a complete vehicle as a donor rig as it can save you a lot of money in the long run when it comes to all the little odds and ends you end up having to buy. I don't think it matters which platform you are going with.
 
Mike,
It's always better to buy a complete vehicle as a donor rig as it can save you a lot of money in the long run when it comes to all the little odds and ends you end up having to buy. I don't think it matters which platform you are going with.
Kinda what I figured. I really should look to get something from the salvage auctions...lot driving, but rusty and not good for anything but the powertrain. Won't take much damage to total it, and around here, not too many people go for the rusty ones.
 
For a guy in the planning stages of a swap, do you think it would be better to buy a whole truck, or just piece together what you need?
Like @Wildman said, buying a full rig is often the best approach. If space allows, this is the best way to ensure you have everything you will need, while also having the opportunity to recoup some $$ in the long run. I did the same when I needed a 5.9L core for my RamCharger. I ended up buying a complete 1999 Ram, pulled the engine, trans, t-case, ECM and some other parts, then sold what was left. I ended up making $$ in the long run.

Now that said, with the popularity of Gen III swaps (Hemi and LS), there are many scrap yards and auto recyclers who will pull everything necessary for you (engine, trans, harness, TPIM, ECM, pedal, etc). You will pay more than you would if you bought a wreck/parts rig, but there is some convenience there.

Wheeling in the sand and mud, I need some horsepower... The 4.slow isn't the right engine. I can't get to it for at least a year, but I might start accumulating parts...
I hear you there... I'm hardly a 4.0L fan. It's a reliable motor, but a tractor motor nonetheless. It took me about 5 months of constant searching to find all the parts I needed and I'm still getting some (some parts I needed other parts to confirm what I need first, exhaust manifolds for example).

For a guy in the planning stages of a swap, do you think it would be better to buy a whole truck, or just piece together what you need? Wheeling in the sand and mud, I need some horsepower... The 4.slow isn't the right engine. I can't get to it for at least a year, but I might start accumulating parts...

By the way, before this thread, I was leaning LS. This thread has me convinced that the hemi is now the way to go. Really nice work, so far.
Both platforms are excellent. For me, the Hemi just makes the most sense since it's the most compatible with what is already in the Jeep (or at least what was available from the factory in certain years). The fact that I can keep it 100% emissions compliant with nothing more than a few locally sourced parts was the biggest advantage. With the Gen III Hemi swaps becoming increasingly popular, the aftermarket support is skyrocketing as well, which only makes it more appealing. Throw in the fact that a set of factory 2009+ Eagle heads will flow over 330 CFM is absolutely bonkers if I ever want to make this thing scream :)
 
If I was starting with my Jeep now and doing a engine swap I'd be seriously looking at a Hemi over the Magnum V-8. But with owning a 1997 with a 01/96 build date I'd have to swap out the gauges & wiring from a newer TJ. It isn't a HUGE issue but it does make it a little more of a hassle compared to starting with a newer TJ.

When I started my swap back in 2005 a Hemi engine & trans take out was $10K if not more since they were basically a new engine which is what kept me from doing the Hemi swap back then. And as pc1p has talked about the 408 stroker he has it's a MONSTER for power but as has been noted before the Hemi or LS will get BETTER MPG than the Magnum.
 
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