I have a completely stock 84 SJ410 and i use it for hunting only. I trailer it everywhere. I was helping a friend get his moose out and while going through a deactivation in the road I found myself stuck with nothing to pull myself out with. because my back end was buried I threw a set of chains on the front and tried to drive out. I ended up breaking the knuckle between the spindle and axle. I found a set of axles for four hundred bucks attached to a decaying LJ80 which I have taken out and proceeded to clean up and put in my SJ  after the troubles i had getting stuck I did some research and decided to go with a fozzy locker front and back. i found this site http://www2.izook.com/?s=fozzy+locker and this site http://www.island4x4.com/4x4tech/axle/weldeddiff1/index.html and this is where i kind of got mixed up. The one site showed welding the side gears , weld two spaces leave two ect, all the way around and the other site showed welding the spider gears. i decided to go with the spider gear site and after reading it carefully ( I thought  ) I went ahead and welded all eight spider gears in the weld one skip one fashion that i thought I had read. Imagine my suprize when going to reassemble i realized that by welding one skipping one all the way around that i had subsequently welded the space for my top side gear to drop onto. i have ground and dremmelled and welded them up apropriately now and will reassemble tomorow. I feel like a dolt but after going back and checking the info it is easy to misinterpit it and the pic showing the after weld is very small and impossible to distinguish where the welds are. so im just saying if you weld the spider gears then make sure you leave two spaces open directly across from each other.   My wife is still laughing her ass off   and as a side note could someone please elaborate on the welding only one tooth and allowing maximum travel before lockup isnt that asking for trouble by allowing momentum and then having it repeatedly stop in the same place all the time?

That is to ease up on the steering (small amount)  if you are running low tire pressure, some times they use lead in there if your worried about breaking. every thing you do to it will have cause and effect, nothing is for free, LOl

my intentions are to just not to have to say whoa in a mud hole
But I am understanding that the weld one space will allow me to have some better turning and easier unlocking of hubs. and since everything is still out of SJ and i have spare spider gears maybe i should go that route for the front and leave the rear the way i have it, pretty much solid.

how much weight you have on your rig is the bigest factor, if your rig is mostly empty and lite I would say weld em both solid and just lock your hubs in when you think you could have the possibility of being stuck.

my intentions are to just not to have to say whoa in a mud hole
But I am understanding that the weld one space will allow me to have some better turning and easier unlocking of hubs. and since everything is still out of SJ and i have spare spider gears maybe i should go that route for the front and leave the rear the way i have it, pretty much solid.

Contrary to popular belief, a Fozzy isn't going to help you much.  You start into a turn and before you know it, it acts like a welded differential. 

A lockrite (or similar product) - under mild load - acts like a normal (but noisy) differential.  Stomp on it and it locks up solid!

It's only benefit is that, because you are not welding everything into a solid blob, your chance of taking the temper off the gears (making the steel brittle) is smaller.

I hope that this helps!

weight wise it varies. but mostly fairly light, but sometimes two guys and our gear. I ended up welding the rear spiders solid except for the two spaces directly across from each other making it pretty much fully locked. as for the front I welded only one space and inserted each spider gear identicaly so i have about 320 degrees of travel on them before they lock up. it will be a few days before i can get it all back together and try it. only one more embarrassing moment when i took a third member from my old front end and rebuilt it and welded it and put it in my rear housing (on the bench) then spent about 3 or 4 frustrating moments trying to get my rear (26 spline axles ) into my (22 spline front side gears ) these are my first difs i have been into in my life so i only felt moderately stupid for not knowing this ahead of time. jeesh it never ends haha. plus im in my carport with a woodstove but it was only -13 today. thanks again for the input.

I have a question to make, Has anyone ran one with any success?I am thinking about running one in the rear of my subaru to allow some turning.then possible in the front diff(which involves a bit of transmission work) depending on how it works in the rear.Other wise I have to pull one of the rear halfshafts to drive on the street.when the only street driving is 30 miles to and from my offroading place that might be ok.However not only would I have to change the halfshaft I also would have to change all 4 tires to the tractor tires when ever I get where I want to go offroad.thats something like an hour of work before I can play and an hour of work when I want/need to go home.With the fozzy locker it would allow some movment so it might make it though turns without locking up.or at the very least make it easier to drive.so has anyone ever ran one?

BTW there are no comercially available lockers for a subaru so if you want a locker it is a lincoln locker or some other variant.

thanks in advance.

i dont have mine mobile as yet but will definately be giving it a test and will gladly give you my opinion at that time.

I would avoid putting anything like a spool in the front end, just having the rear locked up is usually more then enough.  Unless this is going to be trail only and you really don't want to spend any money then I would spend the extra bucks and get a lockright for the front. 

On my trail rig I switched to an ARB up front and kept the spool in the back, and the difference in turning between the ARB on open and the lockright is astounding.  I also don't use the ARB much except on loose hill climbs or rocks when I simply don't feel like playing around with possible lack of traction.

On the SJ-410, if your going to wheel a lot I would look at upgrading to SJ-413/Samurai axles.  A bit wider and a lot easier to find parts for.  Just requires re-welding all the spring mounts.