I boght my yj about a year ago and i'm going to college now and need a lot more power for the freeway. I really want to keep it and was woundering how much altogether a swap to a 4.0 would cost. And what kinds of things I would need for the swap.
Thanx

The quick answer is A Lot!!!! The swap is not just a simple drop in a 4.0L and go. Most of the folks I have chatted with about the swap (i have a 4 banggor 2) said many people ditch the project half way through because it is so much work.
A few thing you will need to swap, 1. axles, unless you have a very and I mean very light foot, 2 if your Yj is newer one then the CPU will need to be swapeed to,,,, plus a hole list of things,

There are a few mod's you can do to your YJ, if your going to use it to drive back and forth to school, you can down size the tires to no bigger then 31"
Some say a bored out TB and sapcer with exhaust, jet chip. etc help, (oh boy I am sure I will get and ear full for that one <img src="/forums/images/graemlins/lol.gif" alt="" /> )

Oh and I forgot the last Mod you can do, just buy a jeep with a 4.0L in it
cheers
Mud

Why would one need to swap axels? As far as I know My 4.0 YJ uses the same axels as a 91 2.5, Dana30 front and Dana 35 rear. The 2.5 should have a lower gear ratio in the axels enabling one to run larger tires with no problem. Depending on the year the transmision might be an issue. the peugot tranny is junk. An ax4 or 5 should be alright. The cost would vary a lot depending on the cost of the 4.0 with acessories and your ability to do the work yourself or not. I would guess 1000 to 2000 dollars. <img src="/forums/images/graemlins/cheers.gif" alt="" />

In order to put a 4.0 in, you would need. A new computer, and wireing harness, a different tranny from a 4.0, and possibly transfer case inpout shaft, and depedning on your current tranny new driveshafts. I wouldn't do it, in the edn it would be cheaper to sell your jeep and get one with a 4.0.

so 1000 to 2000 would be enough if i did it my self or if i didn't..? and would that estimation be for everything..?
thanx

i already tried to down size my tires, i have 32s on my jeep right now and it still doesn't go much faster then 50. should i try a turbo charger..?

More of a wild guess than an estimation, but I mean doing the work yourself I guess. <img src="/forums/images/graemlins/notooth.gif" alt="" /> Sorry dude, there's just too many variables.

I notice NO information about what you have now other than a 4 cyl Jeep unless the 1994 part of your handle is a clue. If you have a 1994 2.5 that won't go over 50 with 32" tires it must be tottaly worn out or else it has other serious problems. My buddy next door has an old (85) CJ with a seriously worn 2.5, Stock gears and 32" tires and he has no problem maintaining 60. If it's freeway speeds you want put some stock size Tires (225 R15?) on that thing and get a tune up.

I bought a good running 4.0 yj complete for 1500. A feller on another thread picked one up for 900. I could swap all the stuff I need for the conversion into my CJ for very little cost by doing the work myself and then selling the left over YJ parts. But I'm not in college! I have time and tools. But wouldn't it make more sense to sell the CJ and fix up the YJ for off road? Enough of my dilemmas, but you can see sunders point I hope.

Your question is just one of those that has no simple answer that you want to hear, I suspect. Don't hold back, feel free to tell us more about what you have now and I'm sure folks on this board will be happy to try and help you get it running better. <img src="/forums/images/graemlins/cheers.gif" alt="" /> <img src="/forums/images/graemlins/cheers.gif" alt="" /> Whatever you decide, Good luck!

SORRY for the delayed reply. yes the axels are the same ie DA 30 or 35 for some 2.5 or 4.0. I was under the impression (and it sound like I may be wrong.. if I am please let me know ) That the added torque from the to the 4.0 (using stock T case for 2.5L) will "pop" the gears (ring and P and spiders). Is that true, (my info comes Via a local shop here in NY,, maybe he just shewed me out of his shop because he didn't want the work?
cheers
Mud

Dude if indeed you have a 94 Wrangler with the 2.5 you most likely have a 4:10 gear and that thing should hiway the same as all others like it. If you have oversize tires the hiway speed will decrease some for every size you go UP! So the best way to get back to normal is to go back to the correct size tire..
Taking that 2.5 fuelie out and installing ANOTHER engine can be a mess. If you go with another fuelie 4.0 you will have to replace wireing and computer and exhaust pipes, radiator, motor mounts, tranny, transfer case and driveshafts... just to get started! It will take months and months of your time and the Jeep will be on blocks all the while..
Are you ready for all this? I AM and I CAN! But I have a shop and plenty of spare time to do $hit like this. If YOU do not have the time, then trade that sucker in on an already six cylinder.. or change back in tire size!
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

The Transfer case used in all but 87 model Wranglers used the same gears in the NP231 case. the ones behind pukejoe and AX-4/5 transmissions used a 21 spline input shaft and the rest use a 23 spline shaft. The input shaft would have to be replaced for fit, not because it's too weak. Ring and pinions would be no more at risk than any stock 4.0 with same gears and tires etc. <img src="/forums/images/graemlins/cheers.gif" alt="" />