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231/231 Doubler

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I am doing this in my XJ, so I will just high light the important info.


I am using the DD machine doubler kit.




Here the plate is mocked up on the range box




Front output cut off




Then I carried the range box and plate to a local machine shop, and 50 bucks later it was welded up. The machine shop used a dancy dancy water cooled TIG and welded the inside as well as the outside.



Here is where it got touchy. I thought my 90 mj t-case was a 23 spline setup.. man was I wrong, it was only a 21 spline setup. This is also when I learned that they are 5 different 23 spline input gears :doh: So after one falied attempt at buying the right input, I ended up tearing down my 231 in my xj. Well this was an epic fail situation. The PO must have been in the case and torn it down, cause it was missing the lil plastic shift owrk parts. This case only ended up being good for the input

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After putting the existing 231's input in the range box I was able to go to the PNP with Jeff and pull another t-case.



MY 23 spline inputs.. of course machine shop couldnt machint them.. they were too hard



Box of parts



Starting over... putting short 23 spline in my old case, then reassembling the new long spline t-case with SYE



The shift fork that was in my 90 mj was a steel one.. first I ever seen like this


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Here is the t-case and range box assembled... I ended up reclocking it to be even flatter




I ended up having to cut my seat bar, and a crap load of floor just to get range box in



Here is how much I had to cut by the tape measure




This is how much I had to cut when I tried using an empty case for a reference...




Keep in mind I still have a t-case drop in plac, and I plan on removing that, so even more will end up getting cut out. My goal is a totally flat bottom

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It is going to be close.. the new floor pan when installed will be touching the seat mounts.. and more then likely I wil have to redo all my seat mounts. BY going flat, it is like giving your self another 1 or so of lift, and since the floor board is all ready cut up.. what diff does it really make :yes: :smart:

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  • 4 weeks later...

Also got some more work done on this today. I removed the t-case drop and got everything in place.




Then I took some driveshafts down to the local machine shop to have them made the right lengths.



After that I realised I had some sheetmetal I could replace.. and he you go



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Got some more work done. I ended up removing and plugging the stock vent, and drilling, tapping and installing a new breather.....








After I got the breather installed.. I assembled the doubler. Everything got loc-tited, and RTV'd. After that was done. I threw some paint on it.. cause everyone knows Good guys wear black








Tommorow's goal.. install doubler, and driveshafts... and Trim fenders. Then eventually make a new x-member and skid for it Will it ever end

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Thanks man..



Well I got some more done.



Here it is all painted up, and assembled





In order to instal the 231 flipped you have to enlarge the bottom 3 holes, or drill all 6 holes out to 5/8 (thats what I did). Also the dry assembled weight is around 100Lbs so have help





By the looks of it, my seat frame mods should be minimum, and I might even be able to repair where I cut out the seat bar on passenger side. Next up is to build a new t-case shifter link age for rear case.. and fix floor, and build a nice x-member foe it.

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  • 3 weeks later...

I havent posted any updates lately so I will post up where I am at.


Started to build the x-member





here is the repair on the seat bar... Came out really nice if you ask me




Here is a pic of the "finished" skid/x-member




I also did some trim work on the fenders... Plans are to make some 1/8 plate tube fenders for the front...


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It basically gives me mutiple choices for t-case gearing. It also gives me 2wd lo. with my current axle ratios I wil have a 114 to 1 first gear ratio in double low. If I can't crawl up it like that.. I can bounce it off the rev limiter and put on a good show :nuts:

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Well this part of the Project is done. Got the floor installed, twin sticks mounted, and seats in. I even test drove it. Double low, and first gear is so slow that it doesnt register on my gps:drool: 5th gear in double low... to the floor registers 15mph:smiley-laughing021:


Floor is coming together. Used a lot of an old xj floor, as well as a healthy amount of 16 guage.



Here I am messing with the placement of the twin sticks




Here the seats and twin sticks are in place. The celice seat are actually really comfortable


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Oh yeah it will give me a huge advantage. I should be able to just about idle over anything i want. Today I also added a aux cooler to help with the power steering from over heating.

ohhh like semi truck :) nice i would like to have like that. creep crawling on anything

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Just posting some pics of my twin sticks. First pic is of my cases in 2wd




second pic is of crawl box being in 4lo, and rear case being in 2wd high.. therefore giving me 2wd low




if both sticks are to the rear... I am in double low. It is going to take some getting used to using the twin sticks, and picking the right gears in the tranny as well. I can now start my truck in double low, and 5th gear:driving:

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