5.9 swap questions

Palerider3

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Mar 24, 2025
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Idaho
Hey guys, I have a 2000 TJ with a 2.5 and ax5 transmission. I'm looking to do a v8 swap and wanting to keep the factory dash and everything else as factory as possible. My buddy has a 99 durango 5.9 that his kid rolled and I can pick up essentially for the price of gas to go get it (4hrs away) and winch it up onto my trailer. My question is, is the 99 durango motor the same ecm style as my 2000 TJ? I'm more of a chevy guy than a Mopar guy so I don't know what years things went together with Mopar stuff. I'd be using the 5.9 and the 46re from the durango and mating it to my 231 case. Would there be a better/easier year to get the engine/trans/harness from to mesh with my TJ? I don't mind looking and waiting and paying more for something if there is a better or simpler version of this for the swap. I'm not really looking for a ton of power either, I just want to do 65 on the highway passes in the mountains here. Any info would be great. Thanks!
 
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Hey guys, I have a 2000 TJ with a 2.5 and ax5 transmission. I'm looking to do a v8 swap and wanting to keep the factory dash and everything else as factory as possible. My buddy has a 99 durango 5.9 that his kid rolled and I can pick up essentially for the price of gas to go get it (4hrs away) and winch it up onto my trailer. My question is, is the 99 durango motor the same ecm style as my 2000 TJ? I'm more of a chevy guy than a Mopar guy so I don't know what years things went together with Mopar stuff. I'd be using the 5.9 and the 46re from the durango and mating it to my 231 case. Would there be a better/easier year to get the engine/trans/harness from to mesh with my TJ? I don't mind looking and waiting and paying more for something if there is a better or simpler version of this for the swap. I'm not really looking for a ton of power either, I just want to do 65 on the highway passes in the mountains here. Any info would be great. Thanks!

Yes the 5.9 Magnum in the Durango is the same as if from a Ram or Dakota. The PCM from the Durango most likely won't work because the Durango came with SKIM or security or both... You're better off finding a PCM from a 5.9 Ram pickup.
To mate all this to your current NP231 you're going to need to change the input gear on your t-case since the 4 cyl & AX-5 has a 21 spline input while the 46RE has a 23 spline. Or find a NP231 from a 6 cyl TJ.
You can use the wiring harness from the Durango to blend with the Jeeps harness. There may be a few extra wires to remove than using a Ram harness but I know people who have done it. There will be a bout 19 wires to blend total.

I see you're in Idaho.. Where @ & if you don't mind me asking where is the rolled rig? I'm just a little west of Ellensburg, WA and have spare parts from a Magnum swap that I pulled out of my TJ when I swapped in a Hemi...

You'll need to either use the current exhaust manifolds or some type of headers. You can use shorties if you have a short arm suspension or block huggers if you have a long arm suspension.
You're going to need to replace the rear axle since the Dana 35 won't live very long behind a V-8... Your two main options are find a Dana 44 from a TJ/LJ or a Ford 8.8... If you want to go the 8.8 route I've got a Barnes truss kit also.

You'll also need a new radiator. I happen to have one or two of them too...

I got some cheat sheets form people who did these swaps before & then some TSB's

You'll want to replace your plenum gasket & most likely replace all your gaskets while you have the engine out. Do the easy maintenance things like the water pump too.

Here's a really good thread on doing the V-8 swap.

https://www.jeepforum.com/threads/wrangler-magnum-v8-discussion.1365878/
 

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I swapped a 99 Durango 5.9 into my 97 2.5 / AX-5 TJ and have about 5k miles on it so far. It's been a great swap that I've really enjoyed as it has good power, utilizes mostly stock parts and looks factory because of that. I don't regret the swap and enjoyed the experience, however, it will absolutely take more time and money than you're figuring. I'll gladly give any pointers to help save either of the previously mentioned commodities.

Speaking of, I need to update my build thread.
 
Wow, Thanks guys! That's some great info. Wildman, I'm a little ways outside of the Boise area to the south so I'm a ways from you but I do drive that way occasionally. The durango is in Elko, NV. I had planned to swap the T-case input because my 231 already has a super short SYE. I also already have rubicon d44s under it and 5.13s. My wheeling style is pretty easy on the gas so I figure they'll hold up fine and I really don't put many miles on it. I figure I'll check compression and leak down on the motor and then if all is well I'll just reseal the engine and trans while it's all on the engine stand. You mentioned you had a radiator or two, what radiator do you recommend with this? I figured I'd run an electric fan just for simplicity also. The truck PCM seems easy to come by for a reman. Do you know if it can be programmed with HPTuners or would I need to actually send it out? I can pull wiring from Shopkey as I have a work account. I really hadn't given exhaust that much thought aside from I'd like it to be quiet-ish.

Dan_Goodwin, Thanks, I may get with you when I get started on this. I like to gather up everything before I get started. Is there anything you needed that you hadn't thought of at first? As for time and money, I add up the costs ahead of time for my projects and thrn just double it now. Lol, I remodeled our bathroom for my ex wife a long time ago and that lesson was really the only good to come of it. Now I just assume I've only thought of half of the expenses and tasks involved.
 
Wow, Thanks guys! That's some great info. Wildman, I'm a little ways outside of the Boise area to the south so I'm a ways from you but I do drive that way occasionally. The durango is in Elko, NV. I had planned to swap the T-case input because my 231 already has a super short SYE. I also already have rubicon d44s under it and 5.13s. My wheeling style is pretty easy on the gas so I figure they'll hold up fine and I really don't put many miles on it. I figure I'll check compression and leak down on the motor and then if all is well I'll just reseal the engine and trans while it's all on the engine stand. You mentioned you had a radiator or two, what radiator do you recommend with this? I figured I'd run an electric fan just for simplicity also. The truck PCM seems easy to come by for a reman. Do you know if it can be programmed with HPTuners or would I need to actually send it out? I can pull wiring from Shopkey as I have a work account. I really hadn't given exhaust that much thought aside from I'd like it to be quiet-ish.

Dan_Goodwin, Thanks, I may get with you when I get started on this. I like to gather up everything before I get started. Is there anything you needed that you hadn't thought of at first? As for time and money, I add up the costs ahead of time for my projects and thrn just double it now. Lol, I remodeled our bathroom for my ex wife a long time ago and that lesson was really the only good to come of it. Now I just assume I've only thought of half of the expenses and tasks involved.

Ryan from FRP uses HPTuners and is very knowledgeable about the Magnum engines. I had a stroker 5.9 in mine until the block cracked so I came across a good deal on the Hemi...
Yes your Dana 44's should hold up just fine unless you're a throttle jockey.

As I said there's folks here that can help as you do things. The #1 issue with the kegger on the Magnum is the plenum gasket blowing and then you sucking oil into the intake. The #2 issue with the Magnum engine is the heads cracking around he exhaust valves. A lot of heads will crack with no issues but then other times you engine up with major issues so doing a compression test & leak down is a good idea. They are actually pretty good engines.

This was one of the heads off my 5.2 Magnum

Cracked head 3.jpg


Cracked head.jpeg


Always glad to help in anyway I can.
 
Wow, Thanks guys! That's some great info. Wildman, I'm a little ways outside of the Boise area to the south so I'm a ways from you but I do drive that way occasionally. The durango is in Elko, NV. I had planned to swap the T-case input because my 231 already has a super short SYE. I also already have rubicon d44s under it and 5.13s. My wheeling style is pretty easy on the gas so I figure they'll hold up fine and I really don't put many miles on it. I figure I'll check compression and leak down on the motor and then if all is well I'll just reseal the engine and trans while it's all on the engine stand. You mentioned you had a radiator or two, what radiator do you recommend with this? I figured I'd run an electric fan just for simplicity also. The truck PCM seems easy to come by for a reman. Do you know if it can be programmed with HPTuners or would I need to actually send it out? I can pull wiring from Shopkey as I have a work account. I really hadn't given exhaust that much thought aside from I'd like it to be quiet-ish.

Dan_Goodwin, Thanks, I may get with you when I get started on this. I like to gather up everything before I get started. Is there anything you needed that you hadn't thought of at first? As for time and money, I add up the costs ahead of time for my projects and thrn just double it now. Lol, I remodeled our bathroom for my ex wife a long time ago and that lesson was really the only good to come of it. Now I just assume I've only thought of half of the expenses and tasks involved.

I did a lot of research, made a spreadsheet with part numbers and saved pictures from forum threads (I can share a link to all of this if you want it) so I had a pretty good idea going in. There was plenty of things I had to source as plans changed along the way though.

I can't stress enough on the importance of keeping parts organized and especially to take tons of pictures of the donor, your jeep and progress along the way.