Axles and Engines


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Hey everyone!
Sorry I have been off the forum for so long, life certainly can get crazy sometimes. Anyways, pretty soon I will be out of training in the Air Force and have some time to work on my Jeep again, and boy do I have some plans for it! Just as a refresher, I have a 1998 TJ with the 2.5L 4 cylinder and the AX5 transmission. I will say that I love how that motor works off-road in sand, crawling, and mud. However, the Jeep is my daily driver, and that 2.5L is AWFUL on the Highway! Even just driving it around town is miserable as it is so low on power. Also, beginning of 2020 I put a rebuilt engine, trans, and transfer case in it because the old one was so worn out. Long story short, I want to put a 6 cylinder in it...specifically the 4.6L Stroker. I have done some reading on it, and if you can get one that is built correctly they can last as long as a regular 4.0L with all the benefits of power to weight ratio. It is very hard to find any information regarding this motor though, so I figured I would make a post asking anyone who has this motor in their Jeep of their opinion. Is it worth the extra money and can you actually tell the difference? How is the reliability?

That brings me to my second issue. With a bigger motor comes the need for some bigger tires. I want to make the jump from 31/10.5/15 to 37/13.5/17. Now I know my rear Dana 35 is a timebomb, especially because it has close to 190,000 miles on it and it makes some noise. So I have been considering running Dana 60s. I want to build it once and forget about it, and the 60s seem to be the answer. I know that a Dana 44 is already a much better option than a Dana 35, but the problem is a few of my buddies have blown D44s with only 35" tires. So my question is what do you suggest? Would a Dana 44 with Chromoly shafts be better? Or should I just go right to D60s? I would also like to run E-Lockers in them. What is yalls experience with them? I guess the drawbacks of a Dana 60 are the ground clearance, weight, and fabrication required to install them. However, I feel that D44s would not last as long.

Anyways, any comments would be greatly appreciated! I am super excited to get this build rolling next year sometime.

Thanks in advance!

Patrick
 

Wildman

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Any time someone asks about doing a engine swap from a 4 cylinder to a 6 cylinder my first response is DON'T. For the amount of work you need to do for the 6 cylinder you could have had a V-8.

And if you're going to add the weight of Dana 60 axles and 37" tires you'll be a lot happier with a V-8.

Either engine swap will require new motor mounts and a new/different transmission. You'll also need a different transfer case or change the input gear from a 21 spline to a 23 spline.
And then you'll also need to change the wiring. Yes you can get a factory harness for the 4.0 but modifying your wiring for a V-8 isn't difficult.
 
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Patrick Carlin
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Hey Wildman,

My train of thought for sticking with the I6 is to get my power to weight ratio up. I have wheeled with a lot of guys that run a V8 and they have a lot more problems than the guys running I6s or I4s. I think that the most common issues regarding the V8 are temperature control and weight. As much as I would like to run a V8, I just don't see myself putting one in this Jeep. I would marry the 4.6L up to an AX15 because they are pretty bulletproof transmissions and hopefully pair that up with an Atlas 2 speed transfer case. I was hoping with the proper gearing, I could offset the weight of the axles and tires. I was told to run at least 4.88s or maybe even 5.13s.
 

AndyG

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Hey Wildman,

My train of thought for sticking with the I6 is to get my power to weight ratio up. I have wheeled with a lot of guys that run a V8 and they have a lot more problems than the guys running I6s or I4s. I think that the most common issues regarding the V8 are temperature control and weight. As much as I would like to run a V8, I just don't see myself putting one in this Jeep. I would marry the 4.6L up to an AX15 because they are pretty bulletproof transmissions and hopefully pair that up with an Atlas 2 speed transfer case. I was hoping with the proper gearing, I could offset the weight of the axles and tires. I was told to run at least 4.88s or maybe even 5.13s.
What vehicle are those V8 engines in sir?

Remember, we want to be as manly as possible here. It takes 101 of us to build a bridge- 100 to build it and 1 to drive a semi across it when it’s done.

Be Manly,
AndyG
 
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Wildman

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Andy and I both have V-8 TJ's mine ran @ 210* or less all the time until I had other engine issues. Mine was a cracked head.
If you check a magnum V-8 (5.2) is about the same weight as a 4.0. I've got the information on my laptop but I'm on my phone.
The power of the 5.2 is more than a 4.6 stroker. And you can run a AX15 behind the 5.2 no problem.

Just giving you real world experience.
 

Wildman

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A 4.0 dry weight is 483 lbs. and a 5.2 is 510 lbs.

A 4.6 is 270 HP & 300 TQ
A 5.2 is 230 HP & 295 TQ but that is a stock output. You can bump that up real easy.

I'm not going to say you won't be happy with the 4.6 stroker. I'm just throwing out other alternatives.

You'll want 5.13 or 5.38 gears if you're going to be running 37" tires. I have 5.13 gears and wish I'd gone to 5.38 gears.

Look at my build thread. I was running 38x12.5x16.5 TSL SX tires when I started this rebuild. So I'm not just talking.

The other thing is you are going to want to stretch your wheel base if you want to run that size of tires.
 
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Patrick Carlin
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Thank you both so much!
I am going to put long arms on it and push the front and rear axles out a bit. I also am going to cut down the axles if I run 60s under it, but I want to keep them wider than the stock width. I also see where you are coming from with the 5.2 swaps. How reliable is it? And is there any adapter needed to bolt it up to the AX15? Also, what was the price of it?
 

Wildman

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You need a Dodge Dakota V-6 bellhousing. That allows the AX15 to bolt up to the V-8. A Dodge magnum V-8 is what you want.
1996-2002 are the years you want.
The nice thing about doing this V-8 swap is that the PCM bolts in the stock position and it will talk to your stock dash so expensive aftermarket gauges are not needed.
Other than the stock heads cracking it's a very reliable engine.
Take the money you'd spend on the 4.6 stroker and rebuild the 5.2 with a good torque cam and aftermarket heads.

I've got tons of links and information about doing the swap in my build thread. There's also other swap threads on the site and the internet.

Make your axles 65" wide. Believe me you'll thank yourself. I'm wishing I'd gone that wide.
 
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Patrick Carlin
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Are you sure you want 37s on a daily driver?
Hell yes! And honestly I am more motivated to do it now that AndyG has challenged my "manliness" with my selection of motors. Also Wildman, I see where you are coming from. I did some reading on your thread and it looks like you now run the 5.9. Are you still wanting to bore it out to a stroker?
 

Wildman

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Hell yes! And honestly I am more motivated to do it now that AndyG has challenged my "manliness" with my selection of motors. Also Wildman, I see where you are coming from. I did some reading on your thread and it looks like you now run the 5.9. Are you still wanting to bore it out to a stroker?

I started with a 5.2 to replace the 2.5 I had so I just swapped the numbers around. It ran OK for 2 years and then started overheating. Which come to find out was a cracked head.
I'd pick up a core 5.9 that I rebuilt but then traded for a 5.9 with a stroker crank. I just rebuilt it and am working on the Jeep to get it ready to set the engine back in.
But I took my longarm lift off and am installing a Savvy midarm instead. Once you read enough on here you'll find that a longarm isn't the preferred suspension. A midarm is the go to setup instead.

So yes I now have a 6.7 stroker engine. And there is a stroker kit for the 5.2 also.

Stroking a 5.2 makes it a 390....


Here is a GREAT but long thread over on JeepForum on doing the Magnum V-8 swap.

 
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Patrick Carlin
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Sorry for the super late reply! I did some reading on the 5.9, and I'm just not too sure that it is the right motor for the build that I want right now. My goal is to put a 1998 block in my Jeep, and I want the full factory wiring harness for it too. My goal is to have it as if it rolled off the factory line as an original 4.0L Jeep with the AX15 tranny. I did some extra reading on the stroker conversion, and everyone seems to say that you can keep all the wiring the same, and just reprogram the ECM to adjust for the extra fuel and air needed. I'm hoping that by doing this if I am to have any issues with it down the line (such as sensors failing, etc.) I can just read the codes and buy OEM parts. Do yall have any inputs on that train of thought? Also in regards to the axles, I am considering buying a set of D60s out of a junkyard and rebuilding them myself. Is it worth the money and effort to do that or should I just buy new?
 

Wildman

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Sorry for the super late reply! I did some reading on the 5.9, and I'm just not too sure that it is the right motor for the build that I want right now. My goal is to put a 1998 block in my Jeep, and I want the full factory wiring harness for it too. My goal is to have it as if it rolled off the factory line as an original 4.0L Jeep with the AX15 tranny. I did some extra reading on the stroker conversion, and everyone seems to say that you can keep all the wiring the same, and just reprogram the ECM to adjust for the extra fuel and air needed. I'm hoping that by doing this if I am to have any issues with it down the line (such as sensors failing, etc.) I can just read the codes and buy OEM parts. Do yall have any inputs on that train of thought? Also in regards to the axles, I am considering buying a set of D60s out of a junkyard and rebuilding them myself. Is it worth the money and effort to do that or should I just buy new?

It's your rig build it how you want to. The V-8 swap is just ONE option. As far as the wiring goes I can plug in a scanner and read the V-8 the same as you can with your stock 4 cyl or a swapped in 6 cyl. Yes you have to blend the two wiring harnesses but it isn't rocket science either.

There are a few people on here who have a stroked 4.0 in their TJ's just do a search and read what they have done.

As far as rebuilding junk yard axles from everything I've read and seen you are just about to the cost of buying a axle from ECGS or other places. Up here in the PNW you can't touch a Dana 60 for under $1K an many are more.

If the largest tire size you're planning on running is 35" tire Dana 44's should be more than enough. But for comparison I broke a Dana 60 on 35" tires so just saying your buddies broke their Dana 44's doesn't mean a lot.
What model of Dana 44? Newer Jeep Dana 44 or old school Dana 44 like from a Ford? What were they doing? A heavy right foot can break anything.
 
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Chris

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Any time someone asks about doing a engine swap from a 4 cylinder to a 6 cylinder my first response is DON'T. For the amount of work you need to do for the 6 cylinder you could have had a V-8.

I agree with this. The 2.5 is an epic turd. The 4.0 is better, but not so much better that I would waste time on the swap. If I was going to do a swap I would swap something that didn’t come in a TJ in the first place.
 
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Patrick Carlin
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My buddy has an LJ, and he is prone to having a heavy foot. He sheered his pinion, ring gear, and spider gears. I rebuilt the axle and he blew it about 2 months later because it had water in it plus he was in some sugar sand. So far, third time is a charm for his axle! I do plan to run 37" tires for now, and eventually throw 40"s on it. That I why I want to do the work putting the bigger axle in it now to save myself some work later on. Once I blow the 60"s, well I guess it will be time to man up and throw some tons under it. Also, I have had a million people tell me it is not worth it to put the 4.0 in a Jeep that came with a 2.5L, but I really want to take on the challenge!:ROFLMAO: My jeep has little to no rust on it and I think it is a great platform to build on.
 

Wildman

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My buddy has an LJ, and he is prone to having a heavy foot. He sheered his pinion, ring gear, and spider gears. I rebuilt the axle and he blew it about 2 months later because it had water in it plus he was in some sugar sand. So far, third time is a charm for his axle! I do plan to run 37" tires for now, and eventually throw 40"s on it. That I why I want to do the work putting the bigger axle in it now to save myself some work later on. Once I blow the 60"s, well I guess it will be time to man up and throw some tons under it. Also, I have had a million people tell me it is not worth it to put the 4.0 in a Jeep that came with a 2.5L, but I really want to take on the challenge!:ROFLMAO: My jeep has little to no rust on it and I think it is a great platform to build on.

In you first post you'd said 35" tires so that is where I got tire size from.

For sure if you're gunna run 37's or 40's get the Dana 60's or a Dana 60 front & 14B rear.

Like I said it's you rig so build it how you want I just tell folks with a 4 cyl who want to swap engines for the work IMO the V-8 is the better choice. But if you're set on the 4.0 then go for it.
 
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Patrick Carlin
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Roger that! My other thought on it is it seems that everyone runs a V-8. I figured I would try to stand out a bit by running a stroker I6. Once I am rich (in my dreams) I'm sure I will have many more Jeeps in my dream garage with every single different engine out there.:ROFLMAO:
 
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Patrick Carlin
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Here is an interesting read! As I said, I hope to find a full 1998 drive train to have rebuilt and bored. Hopefully everything is as plug and play as they say!
 

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Look for a 05+ Super Duty Front, and a Sterling or 14B with disk brake rear. You can pick them up cheap and a set of F450 shafts is like $400 for the front. You would have a rough time breaking those on 37's. I have seen guys do it on 40's but it takes a lot of effort.

I just grabbed a 05+ 60 front and a 08 14B out of a gas Chevy for $750 for the pair.

If you can do the work its less than 1/3 of new from ECGS, and everything will be new besides the housings.