I have to admit I was very nervous to start this task. I have never done any work on transmissions and it was difficult to find a YouTube video or other how tos covering a Subaru 6sp tear down. I read (multiple times) the LSD install stickie by Hindsight and even printed out part of it to set the backlash. So I printed out the whole 6sp transmission section of the FSM and decided to jump in. At the time I had already removed the tail housing and the center diff so the back end was already exposed. I also followed Hobby's 6sp FWD conversion post and had cut off the top part of the center diff to have my 2 pieces to weld together to slave the driven and pinion gears. I was using a Go-Pro while I did the tear down to record video to revisit or maybe even compile a how to video, but quickly realized I am no Vlogger. Once I received the Quaife QDH3Y LSD and the gasket and seal 32001AA210 kit I was ready to go.
IMG_1011.jpg

I did find a NASIOC post about 6spd gear upgrade and it has IMGUR links to photos which worked at the time, but now seem to be broken. This helped to get better visuals, but all in all the FSM was pretty good. As always there were some steps that were not explicitly mentioned that I learned in the end. It was pretty straight forward to remove the oil pump assembly, neutral spring from the striking rod, and remove the transmission case. I did miss the 3 nuts that go with the 8 bolts to hold the transmission case to the adapter plate. Should have known when something requires a lot of force it is probably due to a hidden bolt/nut rather than trying to use force to separate the case. I was wedging a blade around the perimeter because I thought it was superior RTV, but nope just missed 3 nuts and then it came right off.
https://forums.nasioc.com/forums/sho...2831498&page=2
IMG_1013.jpgIMG_1016.jpgIMG_1019.jpg

I continued to follow the FSM once the case was off because this is when the NASIOC links went dead. Once I was able to figure out which was 4th gear and get it shifted then I was able to be prepared to remove the reverse idle, reverse assembly, striking rod, pinion gear, and main driven gear sets. One thing here to note on the reassembly once you put the gear sets and striking rod back in is to note the offset. There are 2 pilot holes on the transmission case which you use to check to make sure it is still in neutral once the case is back on. These 2 holes are ~36mm (IIRC) apart which correlates to the distance you need offset the main gear clutch forks. When you drop in the clutch forks they just drop in and rest on the adapter plate, but the reverse clutch fork seem to always be at the correct height. So once I reinstalled the case for the first time I notice the bottom portion of the striking rod was too low and you could not see it through the lower pilot hole on the transmission case. So you need to make sure all of the clutch forks are shifted into neutral per the FSM and then raise them up to meet the reverse fork to get the outer lobes to be ~36mm apart and align with the pilot holes. You can see the correct offset in the first picture because this is before they were removed and in the right place. I forgot to take a picture of it reassembled.
IMG_1020.jpgIMG_1021.jpg

I was able to lean the transmission down to be horizontal again which allowed me to gently pull out the gears. NOTE this may cause a mess if you have a lot of oil still in it which I did have to clean up a bit of. I was able to use an adjustable spanner wrench to remove the sun dials which hold the front differential in place. Surprisingly it worked really well, but you do need to be careful because you could break the teeth if you don't find one of the grooves. I was able to "gently" pull off the bearings to reuse them and kept the outer races installed in the sun dials. I checked to make sure the bearings still spun nicely and cleaned them off for reinstall. I replaced the oil seals in the sun dials. I heated up the bearings to 200F in my oven, not sure my wife appreciated that, but it worked really well to allow just enough clearance to slip the bearing onto the LSD. Note for the 6sp it did come with special spacers so I put them onto the LSD per their drawing before the bearings. There was some gaps here, but these were taken up when I performed the bearing preload when I set the backlash. Here is the picture of the LSD installed back into the housing. I used the same heat treatment to reinstall the pinion gear onto the LSD. Note the bolts used to hold the pinion gear to the LSD are E20 and not Torx. A puller tool came in handy to remove the oil gear on the VCD housing, remove the carrier bearings on the old front diff, remove the pinion gear from the old front diff and in the end pull or compress the oil gear back on.
IMG_1035.jpg

Since I did not touch anything on the pinion shaft I was able to reinstall it as is and did not need to adjust and spacers. This was also noted in the LSD install stickie so I went with it. Here is where I found it easier to follow the stickie rather than the FSM to set the backlash. The FSM language was a little vague an the pictures did not help too much, but the stickie was perfect. I came up with a similar set up to set a dial indicator on the pinion gear, a vice grip on the pinion shaft, and a weight to hold the shaft fixed. It took me 5-6 tries and adjustments until I was satisfied with my setting. The dial indicator was hard to set and seemed to move on me so this is maybe where using one attached to a steel plate would have been better. I was able to get the backlash set to 0.060" which is right in spec and was able to repeat the measurement. I also set the bearing preload at the same time. It spins nicely and has a good feel to the backlash (ha with my novice experience).
IMG_1036.jpg

Working backwards to get everything reinstalled took a little time. Mostly due to what I learned about the offset of the clutch forks from the adapter plate so I could shift through all of the gears nicely. I did have to clean off some RTV learning this, but luckily I caught it before it had set. This was where I stopped to recording video, but you could use the early part of the video to work backwards and I could talk through it if I upload it someday. I did need an extra set of hands to line up the main driven gear set, pinion gear, and clutch forks to get them all back into the adapter plate. Understanding how the striking rod worked to shift through the gears took a few minutes to grasp but you can figure it out. During the reassembly I went through and replaced all of the copper washers along the way. Luckily I can say reassembled I was able to shift through all 6 gears.

Part of this process was completing the 6sp FWD conversion documented by Hobby. So as mentioned I was able to follow his steps and cut off the top of the VCD housing and needed to weld it to the gear that fit on the end of the pinion shaft. I had tried welding once or twice in high school, but never got any skills. So I waiting for the Easy Flux 125 to go on sale at HF, bought some junk metal scrap, and started practicing. I still need practice, but I was able to get some decent practice welds and get the right settings. So I was nervous to apply this new skill to real parts that need to be structurally welded together, but decided to go for it. Since the parts are pretty thick steel it helped to be able to add extra heat/material to offset my lack of skill. I think it came out pretty clean and a decent weld for my first part. I then got a 1" ID collar, added 2 more set screws to it, and ground flat spots in the pinion shaft where the set screws would sit. As mentioned in Hobby's write up I also cut off the extra portion of the pinion shaft that is no longer needed. I dropped the FWD conversion onto the gears, the collar on top, blue Loctite to the set screws, and it is now installed.
IMG_1075.jpgIMG_1080.jpg

At this point the transmission is back together and just needs the tail housing to be reinstalled. To do so I need to cut off the 4.75" as directed by FFR and then either weld in or JB weld in plugs to cover the holes. I then plan to paint the whole transmission with Eastwood Acrylic Alumna Blast paint so it will look newish again .