Update:

No luck, I'm pretty sure this thing is shot. Now when moving in reverse, it'll go a few feet & then kind of lock up as though it's in park.

Any suggestions for a rebuilder in or around Omaha? How much could I expect to reasonably pay for this? On the other hand if I luck out & am able to source the parts, it may be time for a 5-spd convert. Thanks again fellas!