Talk me out of 37s
- Thread starter PNW_LJ
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OP
@mrblaine have you seen folks have trouble wheeling with JK/JL swaps? I'm sure there are enough guys in your area looking to save some monies vs. going curry axles..
I have seen issues. I won't build another JK front axle if that tells you anything. Also, be aware that there is more than one width JL axle. If I couldn't get them out of a Rubicon, I'd pass. I think it is the Willy's edition that is a stand alone axle size so watch out for that.
It's fine on the street and highway. I can keep it at 70mph most of the time. Some struggle going up steep grades, but that's probably more because of the 42RLE. I have no complaints. Though I wouldn't mind upgrading the front to a 60 someday.
I don't go wheeling as much as I'd like, but I am still using the original ball joints. I think it's been 4 or 5 years.
OP
OK, that helps. JK axles are out for sure at this point. I know Gerald had good luck with a JT axle swap into an LJ. But not sure if I could fab all the brackets myself.
Could always go coilovers
Rubicons and Mojave's come with come with the upgraded axles. These are the wider ones too. Most of the other jeeps have ... I guess lets call them dana 30s? Dont know for sure what they are called, but smaller/weaker. I think there are a few JT sports with a HD tow package that have the stronger axles too, but with out the lockers. The 392's use the Rubicon axles, but without the fad and also with cast iron knuckles.
OP
OP
Probably keeping the original 103", since I don't plan on going over 37s any time soon. I'm not sure if the midarm would affect it a tad bit.
Cool! You can air down from 26 to 25.
Are those from savvy designz? They are dope, brah!
I'm the wrong person to be trying to talk you OUT of running 37" tires. I'm going with 38x13.5x17 M/T Baja Pro XS tires. I'm on a TJ so I had to stretch my WB some. I've got 5" in the rear & 2.75" in the front.
For axles I'm running a TeraLow CRD60 in the rear & a Ford HP44 in the front. I used ball joints before but will be installing American Off-Road's ball joint delete's once he has then available. The Ford HP44 isn't like the TJ/JK Dana 44's but they are becoming harder to find.
I've got the Savvy mid arm on my rig also.
My previous setup was a Nth Degree longarm kit & was running TSL SX 38x12.5x16.5 tires on a 95" WB.
I would definitely decide what your MAX size tire will end up being before you buy axles. I made some mistakes with mine & wish that I'd gone wider than 61" WMS to at least 63.5-65" WMS for better clearance. But as you know it's a fine line of tradeoff between width for stability & clearance & then being able to fit thru the trees. I can't comment on the strengths of the new JL/JT axles but American Iron does offer deletes for them.
For axles I'm running a TeraLow CRD60 in the rear & a Ford HP44 in the front. I used ball joints before but will be installing American Off-Road's ball joint delete's once he has then available. The Ford HP44 isn't like the TJ/JK Dana 44's but they are becoming harder to find.
I've got the Savvy mid arm on my rig also.
My previous setup was a Nth Degree longarm kit & was running TSL SX 38x12.5x16.5 tires on a 95" WB.
I would definitely decide what your MAX size tire will end up being before you buy axles. I made some mistakes with mine & wish that I'd gone wider than 61" WMS to at least 63.5-65" WMS for better clearance. But as you know it's a fine line of tradeoff between width for stability & clearance & then being able to fit thru the trees. I can't comment on the strengths of the new JL/JT axles but American Iron does offer deletes for them.
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My questions are:
1. Does anyone have direct experience with an axle swap like this? How much of a PITA was it to build everything the right way, minimizing bump steer/flexsteer etc?
2. Has anyone done a JL/JT axle swap specifically? They're way beefier than JK axles, but no one offers a swap truss kit for JL axles into TJ as of yet.
3. How bad are the 37s with 5.38s and 4.0 as a daily driver?
So let me know whether this is reasonable or if I'm talking out of my rear end
I most certainly will NOT try to talk you out of 37s, misery loves company
My biggest complaint by far with 37s is driving on the highway. I have 5.13's (i will be changing eventually to 5.38) and the 42RLE just BOGS going up hills at highway speeds. It's do-able dont get me wrong, but I would LOVE a modern transmission where i could hold gears and doesn't suffer from the .69 OD of the 42RLE.
Yes i have direct JK swap experience. It was WAY over my skill level when i started but Blaine's guidance and Toximus's write-up on coilover swap made it approachable. Anyone can do it, and I'd be more than happy to help you out some. You can see my build if you want all the dirty details, it's pretty in depth. Here's the first post of the coilover swap: https://wranglertjforum.com/threads...e-the-3-rs-of-a-first-build.30419/post-505248. That being said i'm going to swap the front JK for a fabricated axle eventually because i want 60 outers with big balljoints, wheel bearings, and selected hubs ... and racer style. I'd be happy to go for a walker valley wheel and show you how the jeep works, its basically what you've spec'd except 5.13 gears.
The weakpoint for me on JK axles are the balljoints. I have a set of balljoint deletes waiting to go in, might start those on Sunday actually. I have like 8000 miles on the Smart Parts "Load SHaring BJs" some pretty hard wheeling with hydro assist on them and i think they're going out.
For a rear axle I went the ECGS 489 with 35 spline and have had zero issues. I would like to swap it only for a high pinion for better rock clearance in the future.
Most Jeeps share outter and inner Cs between 30s and 44s. If I recall correctly a Jeep 44 isn't a "true" 44 as much as it's a 30 with a 44 diff.
I'd either beef up your existing axles...I sleeved and trussed my 30 but I'm on 33s and planning for 35s (and dreaming of 37s). That was as much an experiment for the experience as much as anything.
Personally if I was going for 37s and could afford it...I'd do a wheelbase stretch and dual 60s with rear steer.
Since I can't afford it I'd throw some trusses and sleeves and braces at your existing axles, throw on 37s and send it.
One good thing about 30s and 44s is weight and smaller housings mean more up travel!
-Mac
I'd either beef up your existing axles...I sleeved and trussed my 30 but I'm on 33s and planning for 35s (and dreaming of 37s). That was as much an experiment for the experience as much as anything.
Personally if I was going for 37s and could afford it...I'd do a wheelbase stretch and dual 60s with rear steer.
Since I can't afford it I'd throw some trusses and sleeves and braces at your existing axles, throw on 37s and send it.
One good thing about 30s and 44s is weight and smaller housings mean more up travel!
-Mac
OP
I most certainly will NOT try to talk you out of 37s, misery loves company
My biggest complaint by far with 37s is driving on the highway. I have 5.13's (i will be changing eventually to 5.38) and the 42RLE just BOGS going up hills at highway speeds. It's do-able dont get me wrong, but I would LOVE a modern transmission where i could hold gears and doesn't suffer from the .69 OD of the 42RLE.
Yes i have direct JK swap experience. It was WAY over my skill level when i started but Blaine's guidance and Toximus's write-up on coilover swap made it approachable. Anyone can do it, and I'd be more than happy to help you out some. You can see my build if you want all the dirty details, it's pretty in depth. Here's the first post of the coilover swap: https://wranglertjforum.com/threads...e-the-3-rs-of-a-first-build.30419/post-505248. That being said i'm going to swap the front JK for a fabricated axle eventually because i want 60 outers with big balljoints, wheel bearings, and selected hubs ... and racer style. I'd be happy to go for a walker valley wheel and show you how the jeep works, its basically what you've spec'd except 5.13 gears.
The weakpoint for me on JK axles are the balljoints. I have a set of balljoint deletes waiting to go in, might start those on Sunday actually. I have like 8000 miles on the Smart Parts "Load SHaring BJs" some pretty hard wheeling with hydro assist on them and i think they're going out.
For a rear axle I went the ECGS 489 with 35 spline and have had zero issues. I would like to swap it only for a high pinion for better rock clearance in the future.
Okay I am definitely sending you a PM!
OP
Full send is the only way.
Seriously tho, I wonder what would fail first with 37s on a HP30/Dana 44 combo. Probably shafts, which you could swap in some RCVs. Then what? Driveshaft ujoint or ring and pinion I would think. Ball joints would lretty much be a consumable.
Definitely not a good idea anyway you look at it.
Full send is the only way.
Seriously tho, I wonder what would fail first with 37s on a HP30/Dana 44 combo. Probably shafts, which you could swap in some RCVs. Then what? Driveshaft ujoint or ring and pinion I would think. Ball joints would lretty much be a consumable.
Definitely not a good idea anyway you look at it.
The weak link in the HP30 is that it still uses the same ball joints. The lower BJ will stretch the yoke under stress which causes the ball joint to fall through which then causes the upper BJ to do the same.
That’s ultimately why I run 38s at the mud park and 35s rock crawling.
If you could strengthen the yoke and BJs in the HP30, then it’d be axle shafts I’d imagine. Which if you had high quality shafts like RGA US made 30 spline shafts front and rear you’d probably be okay but spares would be smart.
I’ve been working on a solution to fix the inner C setup for about a year now.
The rear Dana 44 can be made stronger. You can run JK R&P which are stronger than the TJ R&P. Can move to 32, 33 or 35 spline I believe. Not sure what the weak link would be here.
More experienced members will chime in I’m sure.