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Discussion Starter #1 (Edited)
Now that I am finally getting around through my divorce, I am going to get back on my buggy that I haven't touched in years. Money is still a bit tight so swapping the motor isn't an option at the moment, but something that I would like to keep in mind for the future. Don't really plan for a large V8, but a built ecotech or something down the road with a few hundred horse power at most. Currently have a 2.5L backed by manual AX-5 and doubler 231/300 that I am surprised lasted as long as it did before tear down. I have been wanting to swap to an auto and I came across a rebuilt manual valve body 904 for $700. Seems like a good deal, but I don't know much about the 904's. I will probably ditch the doubler and go for an Atlas if I go this route. I am not extremely experienced with Auto's so I guess my question is if this is a good route to go? Axles are 1 tons with 5:13's and running 40" or 42" tires, so what ratio would be ideal on the Atlas also?
 

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If i'm not mistaken, I have a few adapters lying around that we made for JHF to adapt a 904 to an ecotech, they didn't come out quite right but can be made to work with about 35 min of elbow grease .

I might be interested in that doubler, is it 21 or 23 spline ?
 

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Discussion Starter #4
If i'm not mistaken, I have a few adapters lying around that we made for JHF to adapt a 904 to an ecotech, they didn't come out quite right but can be made to work with about 35 min of elbow grease .

I might be interested in that doubler, is it 21 or 23 spline ?
It is the 21 spline gear box from the stock 231 I had.
 

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Discussion Starter #6 (Edited)
I could change out the planetary to 23, is it a NWF or Klune or what ?
It was the DD machine doubler kit that they made years back. Similar to the Box4Rox one that was also made. I don't know if they are still in business though. It is the planetary section of the 231 cut and welded with adapter plate mated to a Dana 300. You should be able to just swap out the planetary gears I believe.

I can take pictures of my set up later, but it looks like this basically.
 

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Discussion Starter #8
For the life of me I can't seem to figure out what flex plate I need. 2.5L from a '91 YJ using a torqueflite 904 auto. Converting from manual to auto, I figured that a flex plate from a '91 YJ with the 2.5L would work just fine. Well, maybe I am missing something here, but nothing seems to add up. The bolt pattern to bolt it to the back of the block is a smaller diameter bolt pattern (about 2 3/8" across). Where the bolt pattern on the flexplate I tried from Napa is more like ~3.5". Am I just an idiot and there is supposed to be a spacer or adapter between? Also the tooth count of my old flywheel is 148 with a 12.5" diameter, but the flex plates that are advertised are 13.83" diameter with 164 teeth..... what the hell am I missing?
 

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I have been considering this swap as well. I picked up a 30rh from another 4cyl Jeep with everything needed. I was going to look at upgrading to an Atlas 4 spd vs my 231/atlas doubler currently. Really like having so many gearing choices.
 
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