I rebuilt the np231 transfer case today, and it went pretty well.
Here it is as removed:
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.
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.
Again it looks like I used too much silicone when sealing the case and it clogged up the filter quite a bit.
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.
The chain and everything looked in pretty good shape. It didn't seem like it was stretched out but I replaced it all anyway.
I replaced the plastic pads on the top shift fork. The lower fork doesn't seem to have pads that are replaceable.
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.
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.
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.
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.
Old and slightly busted, new and complete:
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.
The rebuild kit came with a bunch of spare parts - or at least I hope so
Here it is as removed:
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.
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.
Again it looks like I used too much silicone when sealing the case and it clogged up the filter quite a bit.
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.
The chain and everything looked in pretty good shape. It didn't seem like it was stretched out but I replaced it all anyway.
I replaced the plastic pads on the top shift fork. The lower fork doesn't seem to have pads that are replaceable.
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.
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.
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.
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.
Old and slightly busted, new and complete:
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.
The rebuild kit came with a bunch of spare parts - or at least I hope so
