No special tools needed. That leakage is coming from a worn out O-ring. The 4 speed while it scares the heck out of some people is actually very easy to rebuild.
Ask for detailed instructions from the supplier. I bought my kit from Dan Williams back in the day..I do believe he photocopied from the factory manual. Follow that and you should be able to tackle it.
I rebuilt my T-10. Scared the hell out of me at first and then I called around and got prices for a rebuild and that scared me even more, lol! Ditto to the tools and just following the break down, it's not hard to do at all. And that is a bad or worn o-ring causing your leak. Make sure you pick up a couple extra at the part store as i mangled a few before I got everything back together.
The o rings have to go on the shift levers from the inside so its basically an overhaul. Call Mark @ toploader heaven. He has a kit that has all the basic wear parts,special tools and easy to follow instructions on CD. Plus he's a heck of a nice guy and if you get stuck you can call him and we'll talk you thru whatever is hanging you up.
btw there is no force to be used in this rebuild....if you feel you are requiring force or you need to shove something...step back get a beer and re-evaulate.
Remember where the detents go!! And take a picture of you shifter assembly before you take it off the tranny.