There should be a port on the side of the box to allow you to add gear oil. Mine had a pipe thread elbow and a plug in it. When I did my rebuild I changed that out for brass and made it a bit taller to increase the amount of oil I could put in.
When I pulled mine out water came pouring out, not a good sign.
The steering on these rigs is stiff and difficult to turn, harder when sitting still. However, they can be rehabbed. There are a couple of REALLY good threads on the forum search them out and follow them. In a nutshell check every link from the tires and wheels to the steering wheel. Check for play in any component, there should not be any play in a new system but one as old as these will have some. Moving the steering wheel should immediately move the tire. I hand about a 1/4 turn in mine.
My 66 was more like steering a cement truck then a Jeep. Until you moved you could not hardly move the wheel. Even while moving it was a wrestling match and would not come back to center. Now that I rebuilt the steering box, replaced tires and wheels, removed the longer shackles, replaced drag link, bell crank, and added axle shims to get the caster back to normal it is 1000 time better.
I am not done yet but it is amazingly better. You can check my build thread to see some of the work.
The best advice would be to read the thread below. Great stuff.
Troubleshooting & Correcting your Steering - Jeep-CJ Forums