I am running the AX-15, because I had 1 and it's lightweight and cheap and it's supposed to last even when tuned to the world HD standard 360 lbs-ft, but I haven't tuned mine. I don't know about the Jeep automatics, but I don't remember seeing anyone running one with this engine, though that doesn't mean they don't exist. The AX-15 from what I've read, really isn't rated for the full torque of this engine and personally I don't like the gearing, but every option I was looking at was $6k or more for what I wanted, so I just stuck with the AX-15. Not to mention, if I dropped the $6k on a transmission, I'd stretch the Jeep and go for 1 ton axles, which wouldn't be cheap and it kind of defeats my purpose for the smaller TJ for me, because I have other options and honestly I really like my 1 ton axles with 1 ton transmission and 1 ton diesel engine in my truck. BTW I'm only running my setups around farms and town and I'm not purposefully going through obstacles or knocking out any well travelled trails that get super rutted up. Keeping my setup "mild" is my practical preference, though obviously I want bigger tires and more torque and all the features.

@ from what I was learning online looks like those Eco diesel 1500 g are the best transmissions for this engine! I just put a fresh 4.0 but definitely gonna be saving up with money for this swap next time around

I have not done a delete yet. I keep my EGR unplugged and I haven't heard of any issues besides a light that comes on. I'd love to actually get the parts from abroad so everything is factory deleted, but it's basically just block the port and the coolant lines too.

It is a lot of work and it never fully ends either. I even did a simple version of this build. Some guys machine and/or search junkyards for every single piece of this puzzle and their results are AMAZING, but the work is also AMAZING to get to that point, though some guys actually do some of this or stuff that's similar to this for a living and that obviously puts them in a different playing field. At the end of the day it's incredibly satisfying being on trails with something you can't easily buy, but it also sucks when you breakdown as well, because you messed up something. However if I can find the time and money to do a project, I still love doing various DIY projects. However there have been many moments I didn't want to be in my garage working on something and wanted to be out camping or just having fun.

That is the right response and your wallet will thank you. I don't regret doing a swap AT ALL, but there's stuff I would have done differently. It just depends on what you want though. If you do a swap, you're the engineer and mechanic until you sell your project. If you just want what you want and can't find it anywhere else and you like fabricating and doing some mechanic work and projects, then just find the right swap or build for you. The 4.0 is an amazing engine. Most Jeep Wranglers and CJs are some of the best vehicles for reliability and when you need to work on them, they don't need too many special tools or even a place to work on them. The parts are plentiful and usually reasonably priced. I can work on my TJ almost anywhere, but I can't fit my truck into my garage very well, so I'm limited on what I can do on it. IMO the biggest thing the 4.0 equipped engines need is torque which is a gearing issue. 3.07s should have been illegal. If you want power though or you want an engine with low-end torque then you can make a case for a different engine. For power I think the LS engines are no-brainers. For torque, I'd say gear change and LS swap. If you just don't want to compromise and you want to be a bit unique in the US, diesel is fun and it's even a bit rebellious. I wish we had more options. I really would like a more compact (compared to say a 6BT or Duramax or whatever) 300+hp diesel engine, but they are almost non-existent in the US and getting that from a smaller displacement engine is going to limit the life of those engines (the R2.8's max hp is probably low 200s and I would doubt the block would ever be able to handle 300 hp for more than a couple runs even with a built motor), though a 4BT and a few others are capable, you're gonna be rolling coal all the time and they're just not well mannered engines in a lighter chassis.

I wouldn't say "from scratch", but I think the details will really make a difference longer term. I would probably start with something, at least a frame, but that's just because I'm not a good enough mechanic and fabricator to go too far from a working vehicle. I would try to build off something that's close to your final goal. On a caveat I love the longevity you're going to get from a new car, but I don't love the repairs in 10 years nor the price. On these 20+ year old vehicles, most of the repairs are simple and cheap. Modern cars are so much more complex, they just aren't great platforms to start, but an older, simple framed vehicle is usually a good starting point. However for a Jeep TJ, you already have one of the best vehicle from OEM EVER made from a reliability and ease and cost of working on stand point, except most Jeep drivers need low end torque for their desired applications and your torque starts being useful around 3,500 rpms. Re-gearing and completely restoring an OEM Jeep TJ, IMO is the BEST choice for the average driver, but driving around at 4k RPMS all the time has drawbacks too, but the 4.0 is a really good engine and those Jeeps are very simple and fairly robust. New Jeeps are better in most ways, but they are more complex and they are very pricey. However for some they are the appropriate starting point. I would actually suggest a frame off full rebuild of a stock TJ if you kind of like Jeeps. I mean full too, because I'd even give the wiring attention too because of the age of these vehicles, the wiring is a problem too. If you are wanting something easy to build from scratch, there's A LOT of super cool buggy type builds out there that would be crazy fun and depending on where you live, can be made street legal.

I do think the VW TDIs are a great fit for these Jeeps and that's the reason I even bought a TJ originally. I got this engine pretty early on and went with it because it's a brand new crate engine and I prefer more displacement in general, especially if you run a typical tune which is the standard around the world to get 360 ft lbs. Early on there were some internet rumors of quality and some of those were from knock offs and not actual Cummins engines, but as we all know if you make something in a country that encourages copy cat engineering, you'll get some of that until they do it enough times to work out the issues. I have not researched much further besides thinking about procuring an ISF 3.8, but I just worry I'm going to get something that's just a bad copy and have no support, plus though I dream of being able to meticulously doing a complete DIY install without a kit, I just don't have the time currently to pursue my ideal build. In any case we'll see about longevity, but considering I started with a high mileage Jeep, I've got other driveline issues, mainly that I screwed up my rear axle rebuild and regear and have to find a time when I can roll this back into the shop and pull that axle and also address some suspension issues in the rear and hunt down a small fuel tank leak. If you want MPG, diesels are very good at just needing as much fuel as your foot and the build desire. If you put this engine in a car or make a Jeep more like a car, you're gonna approach 40 mpg by essentially being more aerodynamic ie either the body needs to be more aerodynamic or you just slow down and do like 40 mph with street tires in a Jeep for example. I have a Dodge 3/4 ton diesel and doing 45 mph I get high 20's mpg, but drive normally and I get 18-20 mpg. If you do a swap of any kind, let me know as I'm a huge fan and I have a YJ with a 4 cylinder that I really want to go crazy with so I want more ideas, though my heart is set on turning it essentially into 1 ton Jeep/truck. Sorry for the late response, I wasn't getting notifications for some reason.

There's EGR and DOC. EGR can just be unplugged, but then your Murphy gauge always shows a fault code which would need to have a programmer deal with, which I personally would suggest if you can find someone you trust and that will also open you up to the more standard 360 ft lb tuning used around the world. I also think the engine would look much "cleaner" without that big EGR on top, so for off-road only applications I would remove it and plate it off just like all modern day US diesel engines should be. DOC doesn't seem to do much unless it gets clogged which I don't love the location of it in a TJ, but am afraid if it's relocated further back in the exhaust that maybe there won't be enough heat under light driving to keep it from staying free flowing, but this is complete guessing and probably a call to Cummins could clarify. Considering I want a muffler too, I'll probably relocate mine to an area that's further back, but easy to remove if I start having some issues. Sorry for the late response, I haven't been getting notifications of comments.

AX15 at the moment. Probably in the future the tr4050.

Do it. It would be very cool and you'd get 40 mpg and it would scoot, especially with a tune.

When I had mud tires and no rack I'd get 26 MPG when I was breaking in the engine. With a roof rack and A/T I would get ~ 24 MPG. Mud tires, lift, regear, roof rack 20 MPG (my mud tires are getting incredibly loud so I think the tires are hurting me right now). I think with a good set of ATs I'd get a couple more MPG. All of those are mixed driving, though it's probably a bit heavier on stop and go driving. With aggressive mud tires and no rack I was getting 11 MPG before the swap and had a lot of trouble maintaining 65 MPH and required a lot of shifting to get better MPG. With good tires, no winch, driving ~50MPH on the highway I was getting 18MPG before. MPG is full of trade offs. If you made enough trade-offs and wanted this engine, you could get 50 MPG. If you want full on performance, I'd guess you'd be getting 15 MPG. When towing or off-road, the Jeep just doesn't seem to use much fuel. If I stick to 2,500 lbs or below for towing, I won't take a huge MPG hit, but the previous drivetrain didn't have the torque to utilize OD on an empty Jeep, so add any towing and maintaining speed required very high RPMs and lower gearing ie 3rd gear for hills and really winding up the 4.0L. If all is equal then typically this swap would get you 40% better MPG. Considering my rig didn't have enough torque for what I like to do and the engine was very old and worn, with many worn components, I got considerably better MPG. I could have easily done a regear and engine rebuild, but I just wanted this Jeep to be a diesel since I can have my torque and MPG, rather than constantly worried about refueling and taking a bunch of extra fuel everywhere and I hate dealing with gas cans in the summer.

I'm really happy with it. It just adds a lot of versatility to such a small vehicle. Even being able to stand on it has it's uses. Only issue is that I clear my garage door by about an inch so I'm a little nervous each time.

@@bugoutjeep8065 With the limited room for off-road supplies, I may have to forgo the purist TJ look and order a Gobi rack in the future. Thank you for the informative reply.

I think Jeeps would be great for off-grid. We've gotta move so much equipment that my Jeeps are mostly for fun and IMO more convenient than all of the 4wheelers, everyone rides around. However I've used mine to move equipment many times especially during recovery stuff. I certainly dream of going off-grid, but it's complicated if I want to do all of the things I do now. I'd love to hear about your off-grid setup. Have you been doing anymore YJ swaps?

Thanks. I'm often not fond of doing repairs in the field, but I figured this was common enough that most MF owners could use it. Below is the video that Bundy Bears Shed has with a split MF 135. It might not be the exact video, but I think this is the one he is able to show you in great detail where everything is. kzbin.info/www/bejne/pnLWq4Ohf5KZe9E

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Thanks. It was a fun project even where I messed up.

I just ran some (2) 3/8 rubber fuel lines to the tank from the Cummins supplied pump, 1 for fuel and 1 for return fuel. The return just empties in a different location and I used the factory fuel pump/level sender, but removed the actual fuel pump and screen and ran the line down to near the bottom of the tank. I think there's a regulator or check valve (I can't remember the correct name) between the fuel pickup line and the fuel going into the pump. I did not use my factory fuel tank, but it's still basically the same procedure. On newer tanks there might be more valves to deal with gasoline vapors, but those are not needed for diesel. Unless Cummins has changed their recommendations, you don't even need a lift pump for their fuel pump. I removed the flap in the fill port as well, because it isn't necessary and some diesel filling stations and some off-road fueling options have larger spouts that will be impacted by that flap. I showed some of the fuel setup here kzbin.info/www/bejne/h4Gan3qtq5xkqLM

The kit was cheaper when I got it, but it's quality stuff that saved A BUNCH of time. I don't have my spreadsheet in front of me, but I think with the engine and kit it was in the vicinity of $16k. I didn't go with AC either. Of course that didn't include gauges, exhaust, considerations for dual battery or large single battery and several other items you'll likely want to add or need to repair. I have been driving my setup for over 3 years I think, though I've had the Jeep down for various maintenance and other builds, but the kit has been pretty much trouble free, besides where I rushed things too much. Also I probably did a few things wrong, because there just were fewer examples to go off of and I made a bunch of assumptions as a novice and in one instance installed some stuff in the wrong order and ended up messing up fairly substantially.

@@bugoutjeep8065 ah OK. That will probably be the route then. Thanks for the input it was extremely helpful. I'll hyu if I got any more questions.

@@dmb1881 yeah definitely. Ask anything, I've looked at so many different options for this build before I settled on this and I'm still looking at new options.

That would be cool. I saw someone put these in an older Volvo and with a few mods the thing could really move and get like 40mpg.

That'll be a cool swap. What transmission and drivetrain are you planning?

I'm getting low 20s. Before the roof rack I was getting mid to high 20s even with mud tires. I'm lifted too and I've regeared and rebuilt the axles so everything is new and tight. It's still better than the 11mpg I was getting with the 4.0L. I'm not tuned either so remember these engines are not tuned for economy but will likely see a 10% increase in economy tuned properly. Typically you're gonna see 40% better fuel economy with a diesel if the gas powertrain was properly setup. In my case the 4 L had to be setup for performance to handle highway and off-road.

20 mpg to 30+ mpg depending on the setup and tuning. You can get over 40 if you want. I don't suggest doing this swap solely for mpg since fuel might be cheaper than the swap.

I didn't use a special cotter pin, but I couldn't find it off the shelf at big box store hardware areas. I found one locally in a cotter pin kit for some equipment at rural king. My shear tube sheared because I was discing and because I don't have a diff lock, I was braking the spinning wheel hard and it popped. It's also a several decades old tractor and I'm sure I'm not the only one to hit the brakes to get a bit more traction.

@@bugoutjeep8065 thanks man appreciate that! I'll go at mine over the holidays and yes I do that do. Lucky it's a shear tube I guess it safes any damage being done. They are great little tractors

@@prime553 yeah and all the gearing looked brand new. Those gears and shafts are built very tough too.

Hello mate g'day from down Under I've had the same trouble and thanks to you after I took the steering wheel and steering box off to check the selectors while I put it back together I saw your video and I've got the same problem so......I Might not be the sharpest tool in the shed but does the split pin just go in at the end of the shaft because there is no hole through the shaft to put the split pin Can you let me know mate please thank you ASAP Cheers 15:18

@@ringerdiggsycobbsy6254 yes the idea of the cotter pin is to not let the coupling slide up the upper shaft leaving you without any rear wheel drive. Be sure to push the pin right down to the head and fully turn the 2 ends in tight otherwise they will get caught on the quadrant levers and shear the pin.

It's a Jeep thing...

Compared to a new vehicle it’s not as expensive. There are ways to do a cheaper swap if you take your time. I think a TDI swap could be a very good option too. All my vehicles are so high mileage and I wanted a relatively “new” drivetrain that was relatively easy to maintain. Rebuilding the 4.0 would be a great move too. The 4.0 is a probably top 10 engines imo. I love an in-line 6.

I think it's made by CBR, but it's the one from Axis Industries.

@@bugoutjeep8065 Thank you! I've watched all of your R2.8 videos and am looking into doing the swap on my 98 Ranger

@@seanthompson9848 that’s awesome post some videos of the build when you can.

Good job. The Duramax 2.8? That would be very cool. But here it's WAY more expensive than $3200 where I'm at in KY. I've got very little interest in V8s for the Jeeps because I've got a ZJ with a V8 already and it's a great for what it is, but I wanted something different in a TJ. My YJ truck I'm planning a 6BT with Allison. It's likely not gonna be cheap, but it'll easily pull most of my farm equipment once I swap in axles and brakes from a 1 ton and stretch it.

@@bugoutjeep8065 That YJ project sounds sick, would love to see some content on it. I'm dreaming stretching my old ranger and doing an r2.8 and SAS swap. Thanks for the video.

Whenever I get a chance I'll start going over it, but right now that project is so far on the backburner, though I'm going to try and acquire some parts. I can buy an international 7.3 V8 diesel pretty cheap from a buddy, but I think ultimately I want to get a 6BT in there with an automatic. I may possibly even pull my 5.9 from my Dodge 2500 one day, if I find an acceptable replacement truck. Send me a link if you do your ranger, it would be a fun swap. When I drive my wife's Tacoma, I dream of swapping in a tuned R2.8 instead of the 4.0 in that truck. I think a 200 hp R2.8 with say a 6 speed auto would be AMAZING in a small truck. It wouldn't be fast, but the transmission wouldn't be constantly shifting. Now a 300+hp diesel in almost any truck would just simply be AWESOME. I keep hoping for a R3.8 one day, but I'm doubting those will ever be allowed in the US.

Also what of your undercarriage is original parts or done prior to planning on the Cummins swap??

I bought the whole install kit from axis to install in my TJ with the ax-15. The kit has been great. It took me about 3 months but I was waiting for parts too. IMO I should have gone slower and pulled the tub and spent more time refreshing the chassis. I did replace a few worn components and replaced all of the brake lines. I absolutely love the r2.8, though part of me wishes I'd put this in a longer wheelbase vehicle that was more capable of towing and a stronger transmission behind the engine so I could tune the r2.8 and do some additional towing, because I need to tow fairly often and I'd love to see what this little engine could do. However the stock tune is great for the TJ but I'll still probably get a tune just cuz the torque really makes a Jeep feel the way a Jeep should have been powered and torque is simply fun. The thing I never anticipated before my build was the fear of having my Jeep stolen or wrecked since it has to be built and not really be bought.

Also I've kept this Jeep mostly stock besides the r2.8 and peripherals. I currently have a 2.5in lift and 1in body lift. With currie front and rear track bars and an anti rock front sway bar. I have arb lockers front and rear with 3.73s with Dana 30/Dana super 35. Still haven't installed an exhaust and my skid plate and transfer case are stock though I'd like to do a tummy tuck and run an Atlas 2 5:1 with Tom woods driveshafts.

Where can you buy the R2.8? Everywhere I look it says out of stock.

I got mine from quick draw brand, it took 7 months to get it and I think it’s a little longer now

I think the TDI is great too. The 2.8 is great if you want a bit more torque and you want a brand new engine. TDI would be really cool in an old CJ. The ALH was my plan for years in my TJ. As far as manufacturing a diesel, they're just not gonna happen in the US due to regulations. Support is gonna not be great for most diesels here, but Cummins dealers are everywhere and they have pretty good service. I've been into VWs for awhile and they're awesome but support in the us is hit or miss beyond forums. In any case I'd love to see your build. I've been talking to the wife about a couple more diesel builds and the TDI is one that's high on my list.

I hope you do some videos when you do the swap. I love seeing diesel swaps

I hope you do some videos when you do the swap. I love seeing diesel swaps

I did not replace any gasket, but I can't remember if there was one there or not. I don't recall having a gasket there either.

@@bugoutjeep8065 Thanks. Great video.

@@sxrichardson Any time I can help, just let me know. Thanks

My Axis adapter keeps my ax-15 exactly at the OEM location. QuickDraw has some different adapters to look at too. Your build sounds awesome already. I agree that mpg has more to do with all the additional volume and fill ups required. The low end torque is really nice with the 2.8 though I wouldn't overlook the VW TDI if you don't need the 306 ft lbs (360 with the non EPA tune). However the easiest and cheapest path is to stick with 4.0, but that diesel grunt just brings a smile to my face. And the torque on the road is just incredible. I wouldn't expect 30mpg with your setup but you'll likely be around 20mpg highway or off road. I was at 11 mpg before so that's a massive improvement for be especially with more gear, higher suspension and roof rack I didn't have before my build.

@@bugoutjeep8065 thanks for the reply, my jeep is fairly heavy tipping the scales at about 5200 lbs and the 4.0 just doesn't seem to have the power to pull hills on the Wyoming roads. I am still pondering this swap.

With the 4.56 ratio, you shouldn't have too much trouble moving that much weight around with the 2.8, but you will likely need the Axis Cooling Package. I towed a 2k lb when empty trailer and about 1k lbs of stuff on that trailer with 3.07s for a week or so and it pulled pretty well in the Jeep, but the Jeep couldn't brake quickly at all. Of course most V8 swaps would move you around too, but the MPG is still going to be rather low. I'd imagine 13 mpg with a V8 vs 20ish with the R2.8. The V8 would be more fun when you want to accelerate quickly, but the 2.8 does not accelerate very quickly, but it'll hold highway speeds pretty easily.

@@davidcamilleridfs690 if I change from the ax15 I’m going to try and go 6 speed auto (even if I manually shift it) and there’s a rear cover/adapter that can save an inch or so from QuickDraw I think. I would definitely go gps speedometer it really simplifies stuff and it gives you some shorter transfer case options. There is a tach wire but often you’ll need some kind of signal adapter. I think eliminating the OEM pcm is the way to go. Also that’s mounted in an area where you need a bigger/dual battery and the pcm takes up space right there at the battery. I got the Dakota digital because my wife liked the look. Some other TJ guys didn’t care for the auto meter but imo it looks good. There’s a repowerowners forum and there’s a couple of really awesome gauge sets I’ve seen used with the r2.8. I didn’t know what I was doing at all with my gauges when I was first trying to get gauges and was trying to utilize the j1939, but that was the wrong path and there’s some awesome options out there including different Murphy gauges though I think those are really limited. I do not have AC, but almost everything I have heard suggests you have to relocate the compressor in the TJ frame. I only know of the $1500 bracket from axis that works, but I could be wrong. I try to pull my doors as soon as it looks warm and I didn’t know my ac worked for over a year since I owned the Jeep and I daily drove it and it was not incredibly cold inside and I feel like a slouch cuz my grandfather didn’t get AC in his Jeep until he was 97.

@@bugoutjeep8065 It seems quick draw has some more reasonable options than axis. They have a mid mount a/c kit for 695.00. I have a black soft top and it gets very hot in the summer where I live. My wife and I took a ride in the badlands last sunday and I had the a/c on because my window sliders don't let a lot of air in. I am still on the fence about spending the money for the conversion, I would love the better fuel economy and increased low end torque, I think I could re-use my new aluminum radiator, my biggest concern is that my wife is having a hard time getting in and out of my jeep as her health degrades, on the other hand I like hard core off road and really want to build a set of snow tracks for the jeep and with a diesel engine it would be much more practical.

I'm bugoutjeep on KZbin, Odysee, Instagram, mewe. I only have alerts set for KZbin and Instagram. Even if you ask me questions here, I'll keep replying. I've also have a couple build pages on some forums, specific to the repower program and Jeep Wrangler TJs and YJs. In fact there's more resources on the TJ forum because a few more people have done the swap.

I have seen a few people pull off some cheap builds, but they tend to be pros or take years to get it running and they tend to have access to machine shops. I love those builds but we don't all have that skill or access or time.

Yes I did.

Less room for sure vs OEM. The R2.8 and the accessories are fairly wide too and the EGR is like having a second battery, except it is there to only hurt the engine and the efficiency. It's the turbo and piping that really gets you with the r2.8. I have a YJ with the 4 cylinder and I do like all that space, but the 4.0 was very good too and the r2.8 isn't too bad.