When I screwed up my second Lock Right install, I was forced to repair the diff.
I had installed the Lock Right springs in ass-backwards (not into the oval slots) and the locker ate them up to the point where the rear diff would no longer pull. Of course I wasn't positive this was the problem until I had disassembled the differential and found the springs virtually gone... as in chewed up... and circulated through my diff bearings and gears.
At that point I was where you are now. I could either locate another diff with the gears I was running... or I could rebuild it myself.
I decided to rebuild it myself. Things you need to decide or acquire before making the decision to rebuild it.
Do you have the tools and capacity to rebuild the diff?
You need to be able to secure the diff when you are carefully crushing down the crush sleeve on the pinion bearing. I had read it takes SERIOUS torque to crush the sleeve down. It most certainly does. You will need a large socket (sorry, I don't recall the exact size, but I'm thinking it was around 25mm) for the pinion nut. You will need to hold the pinion yoke while turning the pinion nut down. I fabricated a jig for holding the pinion yoke while I tightened down the pinion nut out of an old pinion yoke with an old lawn mower axle welded to it. The axle was about 36" long. You need every bit of the leverage. I damned near torqued my large vice right out of my workbench.
You will also need a torque wrench that you can measure inch pounds with. As I recall, the final inch pound load/drag on the pinion bearing is right at 14 inch pounds (rotating force of the pinion WITH the diff gear installed).
A bearing press would be helpful. A small one will do.
On the plus side, rebuilding a diff using the same ring and pinion is simpler than setting up a new ring and pinion into the diff. You can use the same pinion shim on the pinion bearing for proper pinion depth. If it were a new or different pinion and ring gear you would probably have to experiment with various shims.
The diff rebuild kit from Low Range cost right at $105. It comes with an assortment of shims and some gear paint to so you can check your tooth pattern before reassembling in order to make necessary bearing pre-load adjustments.
I bought a 1/4" inch pound torque wrench for about $30. I fabbed the diff yoke holding tool. So I guess I had around #135-$150 in the rebuild +/-. I also installed my Lock Right back into it. I've been running it for around 16K+ miles and so far, so good.
So, IF your ring and pinion gears aren't chewed up or worn excessively into a new wear pattern, you should be able to rebuild it cheaper than replacing it. I am NOT a certified mechanic but I am a certified insane Suzuki owner and I was able to perform the diff rebuild.
I had opened up the Suzuki diffs a few times for Lock Right installs, etc, but this was the first (and only to date) time I completely disassembled and rebuilt the entire diff. I have to say there is a bit of satisfaction in completing the task. In addition, I now know my diff will be good-to-go for another hundred thousand+ miles.
I had a set of 5.12 gears I could have swapped into my truck... but after giving it thought, I like the 4.88 ratio for what I use my truck for and besides, I had no idea of how many miles are on the set of 5.12 diffs I have. I don't worry about the front diff bearings simply because they don't see the continual usage and wear the rear diffs see.
