can't pinpoint the leak...

There's a whole host of stuff that could be leaking. If you are using trans fluid in your steering gear it could be misleading you. I try not to use trans fluid in my steering box, only power steering fluid, but...I'd degrease/gunk the entire engine, k frame, steering gear and underside of the trans at the local car wash and start looking as soon as I got home from driving it back.
The trans could be leaking from the valve body seal in the case, the converter seal, the speedo cable, the coolor lines (as mentioned) or it could be the seals in the steering box or pump.