The second time I had a problem with my front diff it wasn't feasible to repair it part by part. I ended-up getting the whole new diff complete for approx. $700 (+/-). Couldn't round up all the parts I needed individually. This was probably 8 - 10 years ago.
The first time I had trouble with it, it was the studs in the carrier that hold the ring gear had broken and I was able to get those and make the repair that lasted a few years before having to replace the diff. Be sure to clean the whole axle housing out super clean before installing your repaired/new diff. I dropped the whole thing out from under the tractor on both repairs to be able to clean/rinse it out with solvent and blow with air. Just 1 single piece of metal or grit can destroy all of your hard work !! Good luck !