I rebuilt the np231 transfer case today, and it went pretty well.
Here it is as removed:
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First thing I did was pressure wash it. And then I used a slightly-too-small hex head socket in the drain plug and stripped it out. It's the same exact thing I did to the fill plug a few months ago, so I took the same tact and ground the threads off of a big-ass bolt so that it fit into the stripped out hole and welded it in. Now I have a matching 19mm headed fill and drain plugs, and I'll never need to buy the right sized hex head.
I popped off the yoke. I don't remember using this much silicone when I installed the slip yoke eliminator. I tried using a little less during this rebuild.
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I pulled off the tail housing after fighting against the silicone for a long time. I just wasn't hitting it hard enough with the rubber hammer to separate the tail from the main housing. Once it broke loose I popped out the seal and bearing and was happy to feel a little bit of grindy-ness when spinning it in my hand. Hopefully replacing this bearing gets rid of the squealing that I've been hearing. I ordered it directly from Teraflex because I assumed it would be a different bearing than the original tail housing. It's a #6207 bearing. I bought two from Teraflex, along with two seals, just in case it's a special kind of bearing and I can't source it down in Baja. Well now I know that you get a 6207 bearing in the standard np231 rebuild kit, so I have two spares.
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Again it looks like I used too much silicone when sealing the case and it clogged up the filter quite a bit.
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Here's my weird looking finger showing you where the oil passage needs to line up. The mounting stud with the nut on it came out when I was separating the transfer case from the transmission. I put some red locktite on it and tightened it back into the transfer case with some vise grips.
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The chain and everything looked in pretty good shape. It didn't seem like it was stretched out but I replaced it all anyway.
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I replaced the plastic pads on the top shift fork. The lower fork doesn't seem to have pads that are replaceable.
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I've got a nice pile of parts going. I kind of like knowing that I get to do all of that degreasing, just slowly and methodically. But I also get weird stress when my only vehicle is in pieces so I kind of have a love-hate relationship with all of those little tasks that just eat up time but need to be done to feel like you did the job right.
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This job was the first time I've seen this kind of snap ring - it just has a little groove for a screwdriver to pop it out of it's nook, and then you get to try to grab it with some other little implement to pry it the whole way out.
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I pulled out the planetary gear to get to the final bearings. The snap ring that keeps in the planetaries is comically large and I wish I'd taken a photo of it.
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This bearing was the hardest part - I don't have any bearing pullers and I'm not sure what kind you'd need, so I just went about chiseling it down and out. It wasn't pretty and I scored the bearing surface a little bit, but not enough to hurt it I pray.
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Old and slightly busted, new and complete:
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Here it is all rebuilt with the new "extended" drain/fill plugs. I debated painting the whole thing but I think I'd rather be able to drive somewhere tomorrow. I put a coat of paint on the cross-member, taking it from orange back to satin black, and I also painted the transmission mount because it was pretty crusty.
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The rebuild kit came with a bunch of spare parts - or at least I hope so
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