My guess is one of the steering box bearings is bad. The bearing balls are separate from the race, I had a shattered race in my O steering box and the shards made grindy noises when turning. It wouldn't hurt like john said to disconnect the steering arm from the front axle and make sure the spindles move freely in the axle. It wouldn't be the first time a half rusted spindle caused issues.

Bill

In praise of doing the simple first: Greased everything up, now it actually turns w/o the grinding noise. Finally drivable.
Question- how much grease shold the stearing gear box actually take? I was having a little trouble with my gun, so I"m not sure how much I put in, but it was A LOT! No grease leaking out anywhere. Should I keep pumping till I see some?
Ran the machine, stopped, regreased, and it worked even better. Almost enjoyable now!
Question 2- is there a way to lube the ball joints?