Would a 4.0 swap into my 2.5 be mostly plug-and-play?

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runninwild

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We were at bantam this weekend and wife and I agreed our 2.5l needs just a few more hp... I've talked on here several times about re gear and then about a 350 swap but I was thinking.....

If I bought a complete tj from 97 -06 that was automatic and had a 4.0 could I just swap everything into my 98 2.5l standard tj ?

( I'm wanting to go to a automatic)

I'll have to see if the auto trans will mount to my np 231j transfer case... but was just curious if it would all be basically plug n play if I had a complete donor other than motor mounts
 
For the most parts yes. The transfer cases may have different input shaft spline counts. They are fairly easy to swap out if needed. If you have axles regeared they may or may not be a good candidate for a 4.0, depends on transmissions I guess.
 
@Obi-Wan I'd like to do a 5.3 vortec but I guess that's the Same as a ls... just not sure about the fuel injection, wiring , everything communicating with each other like the dash etc..
 
I'd probably go try and find a tj with a 42rle transmission seems that adding a cooler is necessary... they supposedly hunt alot for o/d not sure if that's true I have a ax-5 I know I'm constantly shifting like a truck driver trying to keep momentum for hills . my jeeps on the heavy side full spare tire swing out rear carrier bumper amp subwoofer gear winch etc
 
Deputy Dodge said:
I've heard it's easier to swap in an LS than a 4.0.
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Not easier at all. The difference is that after all that work - call it about the same for either option - you wind up with an LS instead of a 4.0…

Edit: What the hell am I saying? LS’s suck!

🙂
 
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runninwild said:
@NashvilleTJ so ls is same amount of work ?
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I’ve never done either of those swaps myself, but running through the list of things you would have to do with either swap, my guess is they are in the ballpark. There are folks on the forum who have done these swaps, so hopefully someone with direct experience will chime in.

It's like comparing an LS swap to a Hemi swap. Both are a lot of work, but in one case you wind up with an LS, and in the other you wind up cool….

🙂

(OP - you probably don’t know me well enough, but my LS buddies here and I are always giving each other good natured shit)
 
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Why not change gearing to the correct ratio for your tire size. You may be happy enough with that. Not sure what that is exactly but it’s at least 4.88
 
runninwild said:
@GPK03X I ws told about 4 or 5k to do it right that is with 4.88 once they get in there I guess they always find more
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A regear should only cost $1200-1600.

You’re front axle is a Dana 30, not Dana 35.

I’m not a fan of swapping a 2.5 for a 4.0. For all the work just do a Magnum V-8 or LS.

EDIT: or Hemi @NashvilleTJ 🤣
 
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They said about $2500 but they said I should probably rebuild my limited slip ( trac-lock) and they usually find more once they get in there... I'd rather do a ls swap I'll have to start collecting parts and figure out how the wiring from the ls engine mates to the jeep harness
 
I'm looking at used ls engines and they are pretty reasonably priced in my area between $500 to $700. Might not be too bad just a bunch of fab work which i have no problem with thanks for everyone's input 👍
 
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