swapping a 2.5 for a 4.0
Thread Starter
Junior Member
Joined: Mar 2009
Posts: 67
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Year: 1999
Model: Cherokee
Engine: 2.5
Well not 100 percent sure on this but I believe the computers and wiring are different. The mounts will be different so there's some fabrication involved to make it fit. Then there's the cooling system to upgrade and then the rear end and so on. It's doable (but almost everything is) but I have never seen it and I would consider it impractical given the cost vs. just buying a 4.0. My change here only, your opinions may differ...
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the computers and wiring are different. The mounts will be different so there's some fabrication involved to make it fit. Then there's the cooling system to upgrade
I have a 95 XJ with typical rust problems has a good 4.0 5spd 231 transfer case. And I just got a 87 MJ that is rust free but has blown 2.5 with 4spd with 4:10s. If I swap wiring computer and such will the whole drive train fit?
Basically you will need the wiring harness from the firewall forward, and the computer and ALL brackets, and associated parts from the 4.0 donor. This includes the frame horns. You MIGHT also need the x-member and t-case shift linkage.
A buddy of mine did this with his MJ... all his parts came from my garage, or the PNP. It took him about 2 months if you do a search on Comancheclub.com you will find the info in the project section.
A buddy of mine did this with his MJ... all his parts came from my garage, or the PNP. It took him about 2 months if you do a search on Comancheclub.com you will find the info in the project section.
Thread Starter
Junior Member
Joined: Mar 2009
Posts: 67
Likes: 0
Year: 1999
Model: Cherokee
Engine: 2.5
Basically you will need the wiring harness from the firewall forward, and the computer and ALL brackets, and associated parts from the 4.0 donor. This includes the frame horns. You MIGHT also need the x-member and t-case shift linkage.
A buddy of mine did this with his MJ... all his parts came from my garage, or the PNP. It took him about 2 months if you do a search on Comancheclub.com you will find the info in the project section.
A buddy of mine did this with his MJ... all his parts came from my garage, or the PNP. It took him about 2 months if you do a search on Comancheclub.com you will find the info in the project section.


