Am new here not new to jeeps by far had a 56 willys m38 95 wrangler 2000 grand cherokee and now currently a 99 tj and my wife has a 98 tj. I am currently in the process of taking out the gutless 2.5 and upgrading to a 4.0 will start a new thread when I start. Goin from a 99 tj 2.5 to a 04 4.0 on a 98 3.0 frame have the engine trans and transfercase from the 04 as well as complete under the hood harness and both harnesses from a 2000 4.0 in the process of this I am adding a 6in rough country lift and thinking of taking the axels off my current frame just cause was told it's got 4.10 gears for the 2.5 only running 31s so the 4.10 with a 4.0 be nice at highway speeds I'm not dumb but not a pro either so it's gonna be a journey I'll be glad to share with you
In process of 2.5 to 4.0 swap
- Thread starter scubasegt
- Start date
That’s a lot of work for a 4.0. Did you think about a v-8? I hope it goes well for you. 
I did but love the 4.0 and never had an issue with them plus already did complete body swap once so not that big of a deal to me wouldn't have to if I cleaned up my frame the first time
That’s a lot of work for a 4.0. Did you think about a v-8? I hope it goes well for you.
Kind of did something similar...my wife folded my 97 in half... bought a 2000 4 cyl frame and tub and did the swap in eight days...
Good luck and you can do it!
You're not going to find much love for a 6" rough country lift here.
I'd follow the thread here and do 4" Currie.
https://wranglertjforum.com/threads/so-you-want-to-run-35-tires-on-your-tj.2428/
-Mac
Good luck and you can do it!
You're not going to find much love for a 6" rough country lift here.
I'd follow the thread here and do 4" Currie.
https://wranglertjforum.com/threads/so-you-want-to-run-35-tires-on-your-tj.2428/
-Mac
You're looking at almost the same amount of work to do the 4.0 swap as it is to do a V-8 swap... Ask me how I know...
I have a 1997 Tj that started life as a SE model though I never felt like my 2.5 was gutless.
I did a Dodge Magnum 5.2 V-8 swap with a 44RE first and drove it for 8 years and then had to park it due to engine issues. There is nothing wrong with the 4.0 other than it isn't know for having that much power either. And yes your 2.5 most likely has 4.10 gears in the axles.
A couple of things:
1) You'll need new motor mounts_ I'm sure you know that but just in case.
2) you say you have a engine from a 04 TJ? Your 99 TJ runs on a CCD bus system and the 04 TJ runs on a PCI bus system. The 2000 harnesses are also CCD bus. To make the 04 engine work it will take a good bit of work.
3) Rough Country suspension systems aren't known for being that great. There are better choices out there.
The 04 engine is distributorless first off so to use that engine you'll need a 2002 or newer engine & dash harness plus a 2002 or newer dash or find a 2001 or below 4.0.
You can't blend the two harnesses together since the CCD & PCI can't talk to each other.
Not sure used affirm to pay for it liked that it came with new springs shocks drop bracket n sway bars
I'd find out. Eventually you'll end up replacing it if you're planning on doing any wheeling. I've wheeled with people that have that lift and it can be downright scary.
Have you looked into what you need to do to be able to run 35" tires on a Dana 35 without breaking it?
Even if you head over to the Iron Range offroad park you will find the limitations of that lift.
On the road you'll realize why it's called ROUGH country
Dana 35's break on the street and trying to run anything over a 33" tire is just asking for it to break. If you want 35" tires then you should do it right. It'll cost you a lot more in the long run not to.