Check out Cap's Service & Repair. They've done right by 4+ vehicles of mine. If they can't work on the Hydramatic themselves, they'll be able to point you in the right direction. https://www.facebook.com/CapsServiceandRepair/ (512) 373-8699
There's some kind of rattle/buzzing sound when cold. I think it's coming from the tranny, but I don't know for sure. Shifts OK, a little flare between 2nd and 3rd but not bad. I can't pinpoint the noise, but it sounds like maybe it's coming from the valve body (?). Anyway, I've got a bigger problem to deal with now on my other toy...