power steering leak - looks like from gear box. Replace?

[centuryhouse]

My 72 GMC C15 (350 engine, TH350 trans, etc) has had a severe ps leak for a while. I replaced the hoses but the leak persists. I ran a towel under the pump & reservoir, and it came up pretty dry. The main leak seems to be under the gear box & rag-joint.

The power steering works great and feels great. I hate to replace working units, but the leak is bad - leaks out entirely within 3 or 4 days.

Do gear boxes often leak? Will a standard parts store replacement work? Should the rag-joint be replaced at the same time?

When I replaced the high pressure hose, it was nowhere like what came off the truck. And neither is any other type I could find when I checked all surrounding years. I'm afraid of buying the gear box and it not being right either.