Holy hell it's been like a year since my last post and I'm sorry to say that not a lot has gotten done other than buying some goodies. I've been spending too much time working on my stupid DD, and other side projects, but yesterday I did finally roll up my sleeves and do some damn work.
Recently, My DD ('05 Legacy GT) chewed up its center diff and I had to replace the trans, and it got me to thinking, since that one is now useless as an AWD trans, I might as well try my hand at making a DIY FWD spline coupler like jpnovac. (
thread here ) So yesterday, I did just that. My center diff looks quite a bit different from JP's but the same general concept carries over and he did an excellent write up.
after removing all of the 14 bolts at the back of my trans, I was able to pull the center diff out
Click to view attachment hammering a pin tool into the little recesses at the top of the diff allowed me to separate the outer casing from the guts
Click to view attachment I then grabbed ahold of the top piece in the stack internals and got to hacking.

I used a cutoff wheel and tried to keep the cut as straight as I could. a little groove in the needle bearing seat made that pretty easy.
Click to view attachment Click to view attachment I then threw the outer casing component in the vice to cut the female splined section off of the rest of the housing, but I didn't have a large enough cutoff wheel to get the job done and I was doing a piss poor job of keeping the cut straight. I knew that at the end of the day, I was going to have to enlist the help of a friend with a welder, so I gave him a ring and asked if he had a bandsaw that might be able to make the cut. He had other methods in mind to cut the component. (I dont think this is how most people use a lathe)
Click to view attachment But hey, it worked and nobody even lost an arm.
Click to view attachment After facing our cylindrical components on the lathe (overkill) we gave the upper edges of the needle bearings a little love with a flapper wheel, and we had our final stack all ready to go. I dropped the smaller cylinder into the larger one and pushed in the needle bearings in to keep the cylinders concentric.
Click to view attachment The side that engages the splines in the trans looked like this.
Click to view attachment we were then ready to weld up the stack.
Click to view attachment Click to view attachment And Viola. After a little facing to flatten up that weld, the DIY spline coupler was complete. You may notice that we didn't weld up the interior of the coupler like JP did in his thread, that mas mostly because my welder friend, Matt didnt think he would be able to get his mig gun into the cylinder to do it cleanly. we discussed the application for a couple minutes and considered the direction that the forces would be applied to this part, and deciced that one weld would
probably hold.... but please, tell me if I'm being an idiot
The component fits up in lovely fashion, and I feel like I've saved a trans from the grave. I'll be doing the final install of the coupler and buttoning up that trans in the coming week, but I'd love to hear the community's thoughts on the coupler.