1998 TJ with 2.5- how to upgrade

[AMC]

Hey guys:

I have a 1998 TJ Wrangler, and I am unsatisfied with the hill climbing power out of the little 2.5 I have in it. I want to put in a 4.0 with air conditioning, as I also lack A.C. It is necessary in summer traffic jams which plague Minneapolis.

My question is: Can I have a 4.0 with air bolted into a 2.5 that didn't come with air? And further, do I have to buy a new transmission? Thank you. There is a 4.0 out of a 2000 cherokee that is for sale and I was told it wouldn't fit.

[pyagid]

It is not a bolt in swap. You would need to weld new frame mounts on, the bellhousing from the tranny to engine is different, you would need a new wiring harness / computer, and I believe the duct work is slightlightly different with A/c. If you wanted to do the swap it is easiest to get a complete donor vehicle that has all the wiring, computers tranny, etc that you may need

-Paul

[youdidwhat]

your diff's will have to be re geared as well. and the ax5 will not handle the power you will need to swap to the ax15.

before you try all the swapping try some power mods first. throttle body extention, cold air intake, new computer chip,

also regearing to somthing like 4.88 or 4.56 would cut th DD aspect down and you would not be able to go as fast on the hwy. but you would have more trail power. most of the 2.5's we run in our club, do not have problems off road it's keeping up on roadf that they lack.

do you run 4low all the time on the trail or are you running 4high?

[AMC]

It is actually my friend's jeep. I just know some one with a 4.0 with ac sitting in his garage and told him, "You may be able to make this swap. Run it by the people on my favorate forum and see what they say." I knew he would need new mounts and drive shafts at a minimum I just thought I would see how tough it would be. I figured it would need a stronger trani too.

[youdidwhat]

It can and has been done before, but for the money and time your friend will be spending to put a 4.0 in you might as well go V8 with it.
some other things I over looked was the PCM and all kinds of sensors, if your friend built a bare bones 360 or the like they could save a ton of wirring nightmares.

don't get me wrong I love my 4.0 and soon will be pulling 230 hp out of her but there are ways to get the power without the hassel.

or like pyagid said get a wreaked 4.0 doner and spend a goodly amount of time pooring over wireing diagrams.

either way good luck with the build see you in MOAB someday.

[Trailbst]

your diff's will have to be re geared as well. and the ax5 will not handle the power you will need to swap to the ax15.

before you try all the swapping try some power mods first. throttle body extention, cold air intake, new computer chip,

also regearing to somthing like 4.88 or 4.56 would cut th DD aspect down and you would not be able to go as fast on the hwy. but you would have more trail power. most of the 2.5's we run in our club, do not have problems off road it's keeping up on roadf that they lack.

do you run 4low all the time on the trail or are you running 4high?

Why do you say he'll have to regear? Chances are, since it's a 4cyl, that it already has 4.10s He's talking about upgrading to a 4.0L, not upgrading his 2.5L

Personally, if he can get a donor Cherokee, I think it would be worth the time and effort to swap the whole driveline in, particularly if the Cherokee is an auto. Grab the whole computer and wiring, and figure out the ducting for the A/C.

You'll have an overdrive Auto, which if I recall correctly, the TJs only had 3spds. You'll have the bigger engine with the better gearing.

If they can stick a Hemi in a TJ, the 4.0L swap can't be too terrible. Might be time intensive, but worth it in the end, IF it's what your friend wants.


Just my $.02


Erik

[youdidwhat]

good point on the 4.10 I was just wondering if the 4.10 in the d35 could handle the power difference. and not run at 3500 rpm at 65 mph.

your right about the AW4 out of the cherokee a 4.0 attached to that would be great, it comes higher HP than the wrangler 4.0 and that tranny is solid.


I just try to cover bases prior to breakage, though with my last trail ride I should have taken my own advice :smile: