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Has anyone ever swapped out the 3.8 and the 4 speed auto out of their 2011 JK and installed the 3.6 and 5 speed auto from a 2012? Looking to see if this was possible to do in my Jeep. Found a great deal on a 3.6 with the 5 speed and my JKU has high miles.
 

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You would have to more than likely swap the entire wiring harness, computer etc.. to make it work. I think it would be cheaper to just buy a 2012. Just my .02
 

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Has anyone ever swapped out the 3.8 and the 4 speed auto out of their 2011 JK and installed the 3.6 and 5 speed auto from a 2012? Looking to see if this was possible to do in my Jeep. Found a great deal on a 3.6 with the 5 speed and my JKU has high miles.
The most expensive projects I've ever done have been a "great deal" on a used part.

The computer systems between the two are very different. So you'll need to swap not only the computers but quite a bit of the wiring harnesses. You'll need a different transfer case (or just the input shaft) since the 5 speed transmission has a different output shaft. The transmission shifter will need to change. You'll need motor mounts, possibly different radiator (at least different hoses), exhaust, etc. etc.

It will cost you a ton of money to swap in an engine in a modern vehicle. But with the Pentastar you end up with a V6 that looks a lot better on paper but really isn't so very much better than the one you're replacing.

If you're going to go to the trouble of swapping engines, you're better off upgrading to something like a Hemi or LS V8. It will cost about the same (maybe a little more) but you'll end up with a whole lot more power and be much happier.

If I had a 3.8 equipped Wrangler and you gave me a free Pentastar and transmission, I'd probably just sell the engine/tranny and do something else with the money.
 

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You could probably sell your jeep with a 3.8 and buy a jeep with a 3.6 for less than the swap will end up costing when all is said and done. It isn't like a little honda civic where everything is pretty much isolated, contained, and standardized so that you could easily swap the engine to a more powerful one in a weekend.

And god forbid you have options on your JK that the donor did not. You would need the dealer to flash and enable them....
 

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I read a thread somewhere that a guy did it. It was lot of work, very involved. The guy was very knowledgeable going into it. He did it for the challenge more than anything.

There are to many other options IMHO, not worth it.
 

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Yes, there have been a couple guys that have done the swap. Both also had full salvage Donor vehicles which would be required.
Bottom line, it’s just as cheap to do a Hemi swap and easier. the Hemi swap kits are readily available. There are NO 3.6 swap kits.


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How about swap from a 3.8L to 4.0L ?

I've yet to hear of anyone swapping in a beloved 4.0L inline six to a JK, but maybe I haven't looked hard enough. Do it with a carb and forget about all that newfangled computerized stuff.
 

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from what I've heard - it takes a lot to make the 3.6 swap work. if you're going to swap, might as well do an LS swap.
 

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Yeah, LS or stay with what you have. I can't imagine spending money to swap in another Chrysler motor.

A buddy of mine has 13k in his LS swap. He got deals on most of the parts and did all the work himself.

Mark

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How about swap from a 3.8L to 4.0L ?

I've yet to hear of anyone swapping in a beloved 4.0L inline six to a JK, but maybe I haven't looked hard enough. Do it with a carb and forget about all that newfangled computerized stuff.
Um. The 4.0 was always fuel injected from the factory.

Besides, there's not enough room nose to tail to fit the straight 6.

If you want a carbureted 258 from an early YJ or CJ, you may as well just wheel that as-is.
 

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Um. The 4.0 was always fuel injected from the factory.

Besides, there's not enough room nose to tail to fit the straight 6.

If you want a carbureted 258 from an early YJ or CJ, you may as well just wheel that as-is.
Um. Didn't say it wasn't.

Wasn't fully serious, other than someone somewhere may have or will have done the swap just out of love for it.
 

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Yeah, LS or stay with what you have. I can't imagine spending money to swap in another Chrysler motor.

A buddy of mine has 13k in his LS swap. He got deals on most of the parts and did all the work himself.

Mark

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yep. OP- I think you can do a 6.0 LS swap installed for 19K or so. check with motech in vegas.
 

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on the jko forum there is a company that makes a harness so it is plug and play or so they say.
 

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The 3.8 is a dog compared to the 3.6. The 285hp 3.6 is the best engine ever put in a Wranger from the factory.
Which isn't saying much. It's hard to imagine a justification for spending money to go from a 3.8 to a 3.6, when there are other, dramatically better, options.

Mark

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The 3.8 is a dog compared to the 3.6. The 285hp 3.6 is the best engine ever put in a Wranger from the factory.


Until you gear that 3.8 properly and there ain’t that much difference. Off road there is no difference. Try stock tires on a 3.8 with 4.56 gears (equivalent with the 3.6 and 3.73) and you would be surprised what the 3.8 can do.
None the less for the cost I would go Hemi or LS.


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That was marketing hype to sell the new and improved Wrangler. You evidently have never driven a properly regeared 3.8.
The 3.8 is 2 gear stops undergeared.

3.6L 5spd Auto with 3.21 is roughly equivalent in gearing to the 3.8L 4spd auto with 4.10.

3.6L 5spd Auto with 4.10 is equivalent to 3.8L 4spd Auto with 4.88.
If you don’t think that makes a huge difference put a Rubicon with 4.10 on the line with a Sahara with 3.21 with same size tires and see it yourself.

Yes, out of the box the 3.6L package is better, but once the mods begin. Not so much.


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That was marketing hype to sell the new and improved Wrangler. You evidently have never driven a properly regeared 3.8.
The 3.8 is 2 gear stops undergeared.

3.6L 5spd Auto with 3.21 is roughly equivalent in gearing to the 3.8L 4spd auto with 4.10.

3.6L 5spd Auto with 4.10 is equivalent to 3.8L 4spd Auto with 4.88.
If you don’t think that makes a huge difference put a Rubicon with 4.10 on the line with a Sahara with 3.21 with same size tires and see it yourself.

Yes, out of the box the 3.6L package is better, but once the mods begin. Not so much.


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You defined what is called "underpowered". Any engine will improve performance with lower gearing... as long as there is enough RPMs to accomodate... which the 3.8 has 1000 less of.

Like you said, the 3.6 is better out of the box. And mod-for-mod it will always outperform the 3.8... always.

If you could prove that the 3.8 was overbuilt and could handle 20+psi of boost on stock internals, now you have a conversation starter. But I don't think that's the case because the Wrangler 3.8 was a 20 year old last gasp of a company that was hemorrhaging. While the 3.6 is the result of a cash and technology infusion. Chrysler themselves even named it "Phoenix" initially. ;)
 
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