You can also try flushing the system by
1: disconnect the return line from the resivoir(sp)
2: plug the hole on the resivoir
3: start the engine, and have a buddy, willing spouse or "life partner" turn the steering wheel back and forth
while you add new fluid as the old fluid is pumped out the disconnected return line. Continue until you are satisfied that all old fluid is removed.
4: Shut down engine, remove plug, reconnect return line, check the level now and after a drive, you are done. Sit back and have a <img src="/forums/images/graemlins/cheers.gif" alt="" />
It's a shot at improvement that shouldn't cost more than a quart of Dextron and 30 min.
Grease is an old timers trick for manual(non-power) steering boxes. When they start to leak drain it and fill it up with grease. For the grease to leak out you'd need a hole like this <img src="/forums/images/graemlins/notooth.gif" alt="" /> in the box.