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Options for JT with Manual Transmission

Zissou

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I've noticed that every V8 swap I've come across is an automatic transmission, and that nearly always gets replaced with a new auto.

I have a manual Mojave on 35's. It's too slow for me, especially getting 13 mpg.
Here's the options I see before me:
  1. Trade it in for a Wrangler 392, when 2024 order banks open.
    1. It has been confirmed the 392 wrangler will be made next year
    2. I placed an order for a '23 392 the day the order banks closed; just my luck. I foresee a price increase on '24s
    3. Resale should be decent on these when it's time to move on though, since it's factory.
  2. Trade it in for a TRX.
    1. TBH I'm into the 392 wrangler more - love having a convertible and the full size trucks are too big for what I want. They cost nearly the same and on paper the TRX is far superior, but idk I guess I'm dumb.
  3. Regear to 4.56 or 4.88's
    1. Finding data on this has proven difficult. It seems to be that manual JTs are super rare, and regears for anything less than 37's are rare.
    2. I don't know if this will make my JT feel any faster in day to day driving - that is ultimately my goal; more torque at sub 4k rpm. Feeling fast is more important than actually being fast and that is subjective.
    3. This is the cheapest option I've listed by miles; $2k vs $40k
  4. V8 swap my Gladiator
    1. The original question; can it even be done with a manual? I'm awaiting Rubitrux's reply; their website only says what they offer is for an auto equipped truck and for anything else inquire about custom jobs.
    2. I don't care if I have to go to an automatic if that's the only path.
    3. The goal would be to swap a 392 in, but a 5.7 hemi would also satisfy my needs.
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Fawkes

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i had asked the exact same question. I have spoken to a few shops that do the V8 swap. Some say they can use the same transmission, two said they would replace it with a manual from a Ram.
 

LouisvEarlleJT

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I'd think it'd be worth trying the regear. If you can afford a 40k swap then what's another 2k just to see if you even need to spend the 40k?
 

JT1

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A regear definitely helps. Will it help enough though?
4.10s on 33's is definitely right on the edge of not enough gear. With 35's 4.56 and 4.88 are both options. 4.56s is probably close to right, but if you want more fun around town and don't drive 80+ on the freeway everywhere, 4.88s are where I'd probably land.

You can try to find a new rubi wrangler 6spd on the lot that has 4.88s. I've seen a few that aren't too far away. That will show you what over-geared feels like on the interstate.

Ultimately, your around town seat of the pants fast feel will be better after a regear, but on the highway, aero kills these things above 80.
 
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Zissou

Zissou

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Got someone from RubiTrux on the phone.
Short answer is yes they will do a 392 swap and source a suitable manual transmission - one of the Getrags. Apparently the transmissions are getting harder to come by and fetching a little higher price. Got estimated that a swap would be about $40k. Have not gotten a formal quote yet.

I also think that because it's a manual the Rubicon transfer case might not be needed, which saves a little bit. I would also be sticking with 35's which saves considerable cost if I were to say go for 40's (and require dana 60's and regearing $$$). I think the largest I'd ever consider running would be 37's.

But good to know it's possible!
Right now I'm waiting to see what happens with this midcycle refresh. If Jeep were to make a 392 Gladiator I'd get that for sure. The Wrangler 392 refresh looks fantastic, but I'm waiting to see the price tag for it. It's got a bunch of upgrades and I doubt those come cheap.
 

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SPED1

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Expensive but.......
https://shiftsst.com/mopar-4wd
or
http://www.rsgear.com/products/off-road-truck-transmissions
Silver State has a TKO based 5 speed off road unit [TKO is a modern toploader style transmission}
Rockland Standard gear has either the NV4500 parts becoming harder to get- or the Magnum 6 speed [4th and 5th gen Camaros, Gtos, Viper and fast Mustangs] converted to accepting a transfer case. All will hold 450 ft lbs torque and magnum will take 600.
 

redriderjf87

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I'd do 4.88's, simple and will help power and mpg.
 

Chaos Theory

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I vote 4.56, which is what I'm going to do. "Power" is relative, but if you have 35's and any kind of additional weight (steel bumpers, winch, etc) like I do, 4.56 will allow you to use the full range of MT gears with a few hundred extra RPMs which will definitely feel more "powerful" for hills, passing, etc. Unless you're rock crawling, 4.88 is too low IMO and actually would detract MPG on highway miles as you'd be in 6th at higher RPMs than necessary. Of course, then there's the altitude discussion...
 

Medical_Bartender

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I just started piecing together/working on a V8 + 1 ton swap for my manual JK (2015 w/ pentasutar V6 & manual tranny). While not entirely the same beast as the gladiator for swapping my research has turned up a little bit of information that may be helpful for you.

First, with all the transmission/clutch drama associated with the manuals in our gladiator, I would avoid keeping the factory 6 speed behind modern V8.

I have a NV4500 that I want to put behind a V8 in my JK. Currently I am debating between a 6.0LS and a 5.7 Hemi. FYI the 2003-2005 Dodge Ram 2500s were spec'd from the factory with the NV4500 transmission behind the Hemi, so that could be an option. I did reach out to advance adapters to see if they could assist me in making this happen and they said they did not offer anything to mate the 5.7 to the NV4500.

I spoke with Motech about the 6.0LS swap + manual transmission and was told it could definitely work but would (obviously) need to be a pretty custom job to get the Jeep + GM computer to talk to each other while also understanding the manual. Keep in mind this is all for an NV4500 because it's what I have and want in my JK.

Another options which will likely be easier would be to find a V8+tremec 6 speed takeout from a wrecked Dodge Challenger. I'm considering doing this if I can't make the NV4500w work but am getting the ton's installed first and will get the engine + transmission sorted after.


Re-gearing would definitely be cheaper and easier depending on your use case. But if you want a V8 manual in these trucks it's going to take some finagling unless you're pockets are deep enough to bring it to one of the reputable 4x4 shops and say "I want a V8 manual, here's my credit card".
 

Rahkmalla

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regear man. It's by far the cheapest option.

I got a 3.6->5.7 manual swap quote of 33.5 reusing my transmission. too rich for my blood
 

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Zissou

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Yeah I'm narrowing down my options in order of cheapest to most expensive:
  1. do nothing and just complain lol
  2. regear to 4.56 nevermind, 4.88's!
  3. buy a wrangler 392 or different truck

I think I am turned off of a V8 swap at this point due to the cost. Even with that swap I don't think I'd keep this truck forever, since I turn over cars so often.
 
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be77solo

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Yeah I'm narrowing down my options in order of cheapest to most expensive:
  1. do nothing and just complain lol
  2. regear to 4.56
  3. buy a wrangler 392 or different truck

I think I am turned off of a V8 swap at this point due to the cost. Even with that swap I don't think I'd keep this truck forever, since I turn over cars so often.
This list seems about right, except you have the manual (same as me), so you're gonna want either 4.88's or maybe 5.13's IMHO..... Most gear talk is about the 8 speed automatics, for some reason most people lump them together, but the ratios are different, and it matters.

Just an additional thought. I run 35's on my manual 6 speed now and excited to get gears woohoo! Did similar on a previous vehicle, gears change everything, awesome improvement for drivability.
 

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  1. regear to 4.56
You're wasting your time with 4.56 unless cruising at high speeds/low RPM is what you're after. If you thought the stock 4.10/33s combo was inadequate (it is), you're basically putting yourself right back into that position with 4.56/35s, only now you've added more unsprung weight and additional rolling mass. Add in additional sprung weight like most of us do; bumpers, winch, cargo, etc, and it just gets worse from there. Plus, you said you're looking for pep, which 4.56 isn't going to give you.

If you want to make a difference with gears and actually feel it, go 4.88. If you're not looking at going 100mph in that thing and want some real zip, throw in 5.13s and get to rowing some gears. Most with 35s/6MT go with 4.88s, however, there are a few of us out there that are going deeper. My 5.13s are sitting in the parts pile in my garage right now. I've stared at more gearing calculation scenarios in the last year than I care to admit, and I'm not the least bit concerned about being over geared. These things are dogs from the factory and should have come with 4.56 to start with.
 
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Zissou

Zissou

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You're wasting your time with 4.56 unless cruising at high speeds/low RPM is what you're after. If you thought the stock 4.10/33s combo was inadequate (it is), you're basically putting yourself right back into that position with 4.56/35s, only now you've added more unsprung weight and additional rolling mass. Add in additional sprung weight like most of us do; bumpers, winch, cargo, etc, and it just gets worse from there. Plus, you said you're looking for pep, which 4.56 isn't going to give you.

If you want to make a difference with gears and actually feel it, go 4.88. If you're not looking at going 100mph in that thing and want some real zip, throw in 5.13s and get to rowing some gears. Most with 35s/6MT go with 4.88s, however, there are a few of us out there that are going deeper. My 5.13s are sitting in the parts pile in my garage right now. I've stared at more gearing calculation scenarios in the last year than I care to admit, and I'm not the least bit concerned about being over geared. These things are dogs from the factory and should have come with 4.56 to start with.

Fair points y'all! Appreciate it
 
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Zissou

Zissou

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Ended up going with option 1; trading it in for something faster. In this case I've ordered a 2024 Wrangler 392.
I'm def going to miss having the pick up bed, but I think I can live without it. There's a U-Haul just down the street for the rare occasions I need to rent a trailer.
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