The 4bt is wayyy to heavy for us and Is not epa compliant or something like that for a 2012. There is an engine that I’m peping on and it’s only a hundred pounds heavier. My KK gets worse mileage then my 80k lbs truck does when towing... it would be nifty to get 600 miles to a tank though huh . It really is sad how little power and gears I have. Just having 2 more gears would be soo very helpful. I’m no speed demon but fully loaded (80k lbs) my truck gets up to speed and maintains 10th gear up any grade while the KK barley can go up a 15 degree incline locked in first flored...

Harleysville is minutes from my house too.

You got major issues that need to be figured out if your KK get's worse mpg's then a OTR truck does at max weight. Have you regeared? PCM/TCM properly configured for tire size?

That means I'm getting better mpg's then you in my KJ that weighs 2000lbs more with the same 3.7 V6.

Spending $10,000-$20,000 to get a few mpg's and a more expensive maintenance bill makes no sense.

the 3.7 is definitely thirsty when towing. 4 gears certiantly don't help, let alone being locked in 3rd gear doing 60. my truck gets anywhere from 9mpg to 11 mpg. plus the trailer im building up is a foot wider then the kk is so its dragging a boat load of air with it. supposedly the engine I want gets 30 mpg not towing. assuming im geared at the trans properly while towing, 20mpg is probably realistic. remember too im a 2012. im just tired of the short comings the 3.7 drive line has and ive always been into diesels. ive already got confirmation that the shop im looking at can do it. the only things that need to be figured out is the cabin electronics. not one piece of the oem drive line besides the rear axle is staying. i dream high and typically meet those dreams with an empty pocket. haha

Don't think your getting anywhere close to 20mpg's with the swap with model year 2012 emissions unless your swapping in a diesel from another vehicle with the correct emission stuff already sorted and works.

To my knowledge I won’t need a dpf on a gasoline vin 2012. If I do this build gets a bit more tricky. Lots of jks swap Cummins in their jeep and some how pass emissions. By lots I mean a handful.

The only Jeeps that can legally pass emissions swapping in a Cummins engine(4BT) is if they are 2005 or older.From what I have read about that new small Cummins is it will need alot of emission stuff to pass since it was not designed for road use.

Regardless of what engine is in the vehicle it must pass emissions for the VIN year.A diesel swap means you can not pass 2012 gas emissions and why it is illegal in most states to swap a diesel in a gas vehicle unless that gas vehicle had a diesel option.

Just because you don't have emission tests does not mean you don't have the responsibility to make it pass .You the current owner will be responsible to make it pass emissions for up to 2 years after you sell it.

People like you are the reason for the insane emission requirements,have to make the "legal" vehicles cleaner to off set all the illegally modified vehicles like you want to build.

And yes I'm being blunt and harsh but it is the truth and your ruining my future of fun with vehicles,not to mention major expense in tools I will need to buy to do my job, just because you want to do something you know is illegal to try and save a buck when you actually will spend 10 times more then if you did a simple fix to your current vehicle like actually regearing correctly for the bigger tires.

Tons of differences between JK swaps and a KK
Start by regearing yours etc then go from there or sell it and buy a vehicle that will pull it
Going to be costly to even attempt to do anything like that
I just pulled a fully packed 6X10 enclosed and fully packed KJ down the Winston Salem NC from Ohio through WVa, Va etc and had no issues at all with power or pulling hills .
Of course 4.10s in it etc helped a ton!

im in between transmissions. still trying to figure out gear ratios that id need to either stick with my 3.73s or 4.10s.

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Maxxis 31x10.50x15

No thought process to it

This is what I mean man... no one has done a complete drive line overhaul on a KK to my knowledge and you’re shooting down ideas... the only reason why the KKs are starting to get more after market parts and thinking outside the box are because people are now not listing to people saying it’s not possible and are thinking outside the box. Calm down and give me a bit to gather parts and get it built.

This is what I mean man... no one has done a complete drive line overhaul on a KK to my knowledge and you’re shooting down ideas... the only reason why the KKs are starting to get more after market parts and thinking outside the box are because people are now not listing to people saying it’s not possible and are thinking outside the box. Calm down and give me a bit to gather parts and get it built.

You know what , we old timers will sit back and wait
although if you think about it, us old timers are what got you better lifts, higher lifts etc for the Libertys with lots of time and experimentation since 2003-2004
been doing this over 40 years and have done a lot of things that people said could not be done , ( like rolling 40s on a Dodge van as a DD back in the late 70s)
But to go into this BS about old timers and the social media crap ( you mean Fake book )
well again we'll sit back and will wait to see what you come up with
Good luck
Its sad when you try and help someone you you get ridiculed
I'm listing now

By the way , truck driver comment, I was too, several million miles over all lower 48 states in a Long nose Pete 379EXHD , Cat , 300 inch wheelbase , 18 speed, so whats ya drive ?