Parts aren't too hard to find. Rebuilders are.
Automatic transmission parts for all makes and models including Hydramatic and Jetaway
Fatsco Transmission Parts
337 ChangeBridge Road
PO Box 635
Pine Brook, NJ 07058
(973)227-2487 or (800) 524-0485
http://www.fatsco.com/index.htmTransmission parts for Hydramatic, etc
Northwest Transmission Parts
13500 US Route 62
Winchester, Ohio 45697
937-442-2811
http://99.152.162.116/nwtparts/Automatic transmission parts 40s –60s, rebuild kits
David Edwards Automatic Transmission Parts
56 Dale Street, Dept. A
Needham Heights, MA 02494-1218
781-449-2065
http://www.autotran.us/