Steel Soldiers Supporter
Sure - and I knew it, but didn't want to discourage you...Installed Barrman's Top Section early this morning, and took her for a drive at first light. No change.
Pulling the MS and disassembling it is not a problem if you have- or can borough a good lock ring pliers set and a (small) shop press. Eventually a bearing puller also, if the output bearing doesn't come off even after some heat-gun treatment.
If you bought a takeout transmission, chances are that you need to rebuild it anyway. Yours seems to be very low mileage, so I would try to fix what's wrong there, first, instead of spending money buying unknown, prob. worn-out parts.