power steering fluid leaks out on 1994 Chevrolet Astro

it seems as though my power steering fluid is leaking out at the gearbox. Anybody familiar with this??

Asked by for the 1994 Chevrolet Astro
where from on the box?
The van has been sitting for a while. I started it the other day. All the fluid has leaked out.As best I can recall it leaks out around a big nut at the top, but i'm not sure. I'll need to get more fluid into the system and let you know precisely where it appears to be leaking.
Thanks for a speedy response.
I finally got around to getting up under the van to see what was going on. It appears that fluid is leaking from around the area where the pittman arm attaches to the gearbox. The fluid runs out at a steady rate while the engine is running but slows to a drip when it's off. Is it possible to tighten that huge nut at the pittman arm and stop the leak?