1998 TJ, 5.9L, 46RE swap and complete rebuid

Junkyard Junkie

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Sep 25, 2018
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Northern New Mexico
Hello All,

Not sure how I missed this forum before, but a TJ only site seems like a good place to hang out for help and thoughts on my newest project.

I got a '98 TJ a few months ago, traded my wife's Durango for it. The Jeep's frame is a complete rust bucket and unsuable. I had to get a new frame to put under the body. There's some rust on the floor pan, but not bad, I will need to weld in some pans and body mounts.

I've always wanted to build a V8 TJ, so this is it.

I got a 2003 Durango RT with 120K miles. I pulled the engine and trany out of it and right now going through both to freshen them up. I will swap all engine and trany sensors to match the older harness and work with the CCD computer.

T case is a NP231J from a 1999 XJ 4.0, auto which bolted right up to the 46re. I'm using stock TJ drive shafts, so the T case will remain in the stock location and I'll weld in the AA engine mounts at that spot.

I have a 1998 Ram 5.9l, auto computer and wiring harness to go with the CCD systm in the TJ (was a 4.0L, 5 speed).

I also have a Ford 8.8, 31 spline, with disk brakes and a XJ, HP D-30.

The TJ came with a 2.5" Tera flex lift NIB and I will use that for now along with a 1 to 2" body lift.

I'm planing 4.56/4.88 gears and 33 to 35" tires.

I'm about 2-3 weeks from putting the drive train onto the frame (I have not put the body on yet and will not be doing so till last)

I'll post some pictures later, but so far so good. No major issues yet, except keep having to buy parts for the trany. This is my first time getting into an auto, so keep getting surprises on what's inside and what needs to be replaced.

About it for now.
 
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I look forward to the photos and following your build! I almost bought a LJ Rubicon that was for sale locally that had the Magnum V8 from a Dodge Durango swapped into it. I got to take it for a test ride and everything. Definitely a lot cheaper (and easier from what I hear?) than a LS or Hemi swap!
 
The Hemi swap will be next. I'm in the hopes of getting a 2008 JKU, Rubicon with a bad engine. Which might happen in the next day or so. Hemi will go good with that.

Right now I want to concentrate on this TJ.

Thanks.
 
Here's some pics of the Jeep, one is the first day home, second is how it sits now, third is the engine almost ready and trany in progress.
Engine got a "lipstick on a pig" make-over. It ran fine before I pulled it, I resealed it, including new head gaskets and a new oil pump and water pump and while everything was off, I repainted it. (You can still see the rusted block and heads, but pretend you can't)

jeep.jpg


current.jpg


engine.jpg
 
Thought I'd have the 8.8 setup and the drivetrain put in this weekend. Man was I wrong, took me 2 days to set up the axle brackets alone and I still need to finish the final welding. That'll have to wait till next weekend. I did tack it all in and did a trial fit, it all seems to be fine. Artec builds a pretty good kit, I would highly recommend it.

rear axle.jpg
 
Looking good so far though, I'm very impressed. I sure wish I knew how to weld. I could have accomplished so much by now!
 
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Looking good so far though, I'm very impressed. I sure wish I knew how to weld. I could have accomplished so much by now!

Honestly, just buy a welder and start welding. It's so much fun, I love it. Do a lot of practice before doing anything structural.
It's easier than you think. Just like doing a ring and pinion swap, that also seems like something that's way too complicated, till you try it and then it's easy.
 
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Honestly, just buy a welder and start welding. It's so much fun, I love it. Do a lot of practice before doing anything structural.
It's easier than you think. Just like doing a ring and pinion swap, that also seems like something that's way too complicated, till you try it and then it's easy.

That was my thought as well. I may just have to buy one and start practicing on all sorts of different metal!
 
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Engine, trany and transfer case are now in. I was going to do the R&P next, but I'm running low on funds. Think I need about 1K to rebuild both axles. I'll likely go with 5.13 gears and 35" tires.

I got a 231 from a 1999 XJ with an auto trany and that bolted to the 46RE. I put the advanced adopter's engine mounts where they were designed to go and everything fit into place with some work. The trany mount/skid plate went in a completely new location, but the AX15 mount fit the 46RE, so at least that part worked out.
I was able to use a stock front drive shaft from a 2.5L TJ, but had to get an SYE because of the lift and the 8.8. The rear was not working out.

I put in a 1" body lift also. There are no clearance issues for anything. Everything fell into place, including the stock exhaust manifolds. This will likely not be everyone's case, if you use other combinations.

The trany took a lot more work then I had expected, I ended up putting in a transgo SK TFOD-jr shift kit to fix the issue of the torque converter not charging in park. Now I can run a trany cooler without a check valve. I rebuilt the valve body and put in new sensors and solenoids. Kind'a wish I had just used the AX15 and avoided all that, but It's done now.

I also replaced the rear two floor pans with 16 gauge steel and bought a new right, front pan. I used rectangular tubing for body mounts. Total cost of rust repair was about $100. Definitely not show quality repair, but I really don't care about the body. To me the body is last thing I was to spend a lot of time or money on. Rust repair is a PITA, it never ends, you just keep finding more and more.

drive shaft.jpg


angle iron.jpg


engine in jeep.jpg
 
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Engine, trany and transfer case are now in. I was going to do the R&P next, but I'm running low on funds. Think I need about 1K to rebuild both axles. I'll likely go with 5.13 gears and 35" tires.

I got a 231 from a 1999 XJ with an auto trany and that bolted to the 46RE. I put the advanced adopter's engine mounts where they were designed to go and everything fit into place with some work. The trany mount/skid plate went in a completely new location, but the AX15 mount fit the 46RE, so at least that part worked out.
I was able to use a stock front drive shaft from a 2.5L TJ, but had to get an SYE because of the lift and the 8.8. The rear was not working out.

I put in a 1" body lift also. There are no clearance issues for anything. Everything fell into place, including the stock exhaust manifolds. This will likely not be everyone's case, if you use other combinations.

The trany took a lot more work then I had expected, I ended up putting in a transgo SK TFOD-jr shift kit to fix the issue of the torque converter not charging in park. Now I can run a trany cooler without a check valve. I rebuilt the valve body and put in new sensors and solenoids. Kind'a wish I had just used the AX15 and avoided all that, but It's done now.

I also replaced the rear two floor pans with 16 gauge steel and bought a new right, front pan. I used rectangular tubing for body mounts. Total cost of rust repair was about $100. Definitely not show quality repair, but I really don't care about the body. To me the body is last thing I was to spend a lot of time or money on. Rust repair is a PITA, it never ends, you just keep finding more and more.

View attachment 71096

View attachment 71097

View attachment 71098
I bought a Jeep with the same swap and I can’t get it to shift out of first speedo also doesn’t work.. issue? I replaced all solenoids in valve body both speed sensors and still nothing
 
I bought a Jeep with the same swap and I can’t get it to shift out of first speedo also doesn’t work.. issue? I replaced all solenoids in valve body both speed sensors and still nothing

Man, I got nothing for you. I am not an expert in anything I do. When ever I run into a problem, I have to figure it out to move forward. I would suggest you try "hotrodders.com" That's has been my go to site for a very long time.

My thoughts are that the speedo not working is related to the transfer case speedo sender, or wiring . The one in the trany is for the computer.

Did it ever shift out of first, or is this a new problem.
 
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I was able to sell another project and got some cash to continue this one. Just bought a set of 5.13 gears and a trac lock rebuild kit. I'm getting a set of used rubicon wheels and tires for $100. I'll run the 32" tires for now. They're dirt cheap and can easily be replaced later. Should be a pretty good kick in the pants with those gears and tires.
Some pics of rust repair.

rear pan.jpg


front pan.jpg


20180704_192822.jpg


new rail.jpg