4.7 V8 II into My KJ

blue_kjR417 · **Posted:** Wed Dec 24, 2008 12:37 pm

Ok, I know everyone probably at one time has thought about this but I'm really interested in possibly trying this! I think the 4.7 V8 II from the 2008-Up Dodge Dakota/Jeep Grand Cherokee/Dodge Durango would be perfect to throw in a KJ and I found that the 09 Grand Cherokee's are available with either the 3.7 V6 from the Liberty's or the 4.7 V8. Therefore the engine mounts must have to be the same correct? Which means one should drop into a KJ. Now I know I've have to either swap computers or reconfigure mine or something. However, would the stock tranny in my KJ hold the 300+ hp from the 4.7? If so thats awesome! But do you guys think the thing would even fit? Here are some pics of the 4.7 V8 in a 2008 Dakota and Grand Cherokee.

305 hp / 334 lb-ft torque

Hood297 · **Posted:** Wed Dec 24, 2008 1:10 pm

well in regards to the tranny, what year is yours? I doubt a 42RLE would like that much power. However the 45RFE could handle it.

That being said, anything can be done if you throw enough money into it. It's going to be much more complicated than just a straight up swap. Im sure TJKJ will come in and give you some exact details on both motors and the pros/cons. He has a lot more knowledge on each of those engines.

blue_kjR417 · **Posted:** Wed Dec 24, 2008 1:23 pm

I have an 05 Renegade

Hood297 · **Posted:** Wed Dec 24, 2008 1:32 pm

Then you have a 42RLE which is actually a "minivan" tranny. The 45RFE which was used in 02's and some 03's is a stronger "truck" tranny, which would be better suited to 4.7L V8.

Im not positive but I don't think your tranny would like the V8. I may be wrong though. I'm sure if I am we will know soon :lol:

tommudd · **Posted:** Wed Dec 24, 2008 1:36 pm

check the 4X2 section
already a whole write up on the pros and cons, 25 years ago would be no problem, with all the computer CRAP today its not as easy as if the motor mounts fit it will work.

rescu2000 · **Posted:** Wed Dec 24, 2008 2:38 pm

Also keep in mind that in some states, it will not pass inspection if you swap an engine in that does not meet specific criteria. I don't recall all of the criteria, but in some states you have to have the computer VIN match the car's VIN. Since you would need the computer with the engine, you would have to have it "modified" somewhere to match, IF your state requires it. Some of the other criteria would be that it has to be from the same manufacturer (which that engine would be). I'm not sure what other things they might require. As for the Tranny, if you are going to the trouble of doing an engine swap I would UNDOUBTEDLY go ahead ans swap in the stronger tranny.

Rescu2000

ATXKJ · **Posted:** Wed Dec 24, 2008 6:29 pm

"Therefore the engine mounts must have to be the same correct?"

No - a company capable of putting 2 different engines in the same body style - is capable of changing motor mounts to match.

They may be - they may not

Tranny should be a concern - as should the computer - and the radiator and a dozen other things that you'll find, as you do the swap - but hey - it's a learning experience.

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

It can be done, but it is not practical. As mentioned, you'll need the computers, and they'll need to be reprogrammed with your VIN and for your sentry keys. If you live in an area with emissions testing, it can't be throwing any codes either. You will need the transmission because the 42RLE will grenade very quickly with that much power. If you're going to run it in 4WD, I seriously doubt the D30A up front will last very long either. So you'll probably end up wanting to do an SFA swap. You'll probably want upgraded axle shafts in the rear, and if you have the trashlock in the rear it probably won't last either. You'll have to deal with the radiator, fan, etc.. but those should be fairly easy if you can take care of everything else. If you have a really large budget, and are ready to spend a few months with the KJ torn apart, please do it. I'd love to see someone do it. We came extremely close to putting a 4.7 HO in mine back in 2004.

blue_kjR417 · **Posted:** Wed Dec 24, 2008 7:06 pm

Well, I live in Arkansas we ain't got no inspection bull doo doo so forget that but I know practicality isn't on my side but what really is practical?

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

No testing here in Lexington, KY either. Practicality isn't exactly something I worry about either. No wife, no kids, good job with good income, do pretty much whatever I want.

XR · **Posted:** Wed Dec 24, 2008 7:33 pm

Practical or not some things aren't worth the headache.

tommudd · **Posted:** Wed Dec 24, 2008 8:12 pm

XR wrote:

Practical or not some things aren't worth the headache.

isn't it the truth!!!
But if you insist on doing it,
buy another DD,
fiqure what it will cost,
then take that times two
determine a time frame
and take that times three
and then start. :wink:

rangerd77 · **Joined:** Sat May 03, 2008 10:48 am **Posts:** 512

TOM thats way too much mathematics man. but i came up $309203787654.02 and 16479276 hours. just over the limit for me and couple hours les and i wouldve thought about it

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

rangerd77 wrote:

TOM thats way too much mathematics man. but i came up $309203787654.02 and 16479276 hours. just over the limit for me and couple hours les and i wouldve thought about it

I think you forgot to carry a number someplace. My numbers came up about $1 billion and 100 years different. You may still be able to do it.

ATXKJ · **Posted:** Wed Dec 24, 2008 8:57 pm

Normally I take the best time estimate - and move to the next unit ie. if the initial plan is hours then the best estimate is days.
days => weeks
weeks=> months

amazing how accurate it is..

off topic - Rangerd77 - your signature is impressive

tommudd · **Posted:** Wed Dec 24, 2008 9:05 pm

So this will be one of those projects that your grandchildren will finish then??? :lol:

rangerd77 · **Joined:** Sat May 03, 2008 10:48 am **Posts:** 512

So this will be one of those projects that your grandchildren will finish then???

well its all up to the girl in my SIG, KRISSY, if she wants kids or not. but thats not a job for me anyway. i mean if the guy that started this thread wants to do it then more power to him. but to me, i wanna do a YJ with a LS1 in it, spring over lift, 16" travel coil overs, etc. alot cheaper and dang near a plug and play project these days.

ObiHann · **Posted:** Thu Dec 25, 2008 9:53 pm

Might be easier to just buy a v8 jeep and fab the liberty body on it

daspes · **Posted:** Thu Dec 25, 2008 10:48 pm

This has been discussed many, many times. Never has been executed, but been talked about repeatedly. Do a search for 4.7 and you should so the majority of posts made on the subject. That being said, IIRC, the 4.7 will bolt in, you will also need the tranny, and all the wiring and electronics. And a custom radiator, I believe you will have to fab a new bracket to move it forward about an inch. Please bear in mind, thats not gospel, and I'm going from memory, on what we've figured out.

Fulltimer · **Posted:** Fri Dec 26, 2008 12:13 am

What about the transfer case?

Terry

4.7 V8 II into My KJ

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