Oil leak out of the speedo cable mounting adapter on the tranny

Should be very simple, probably just need a new o-ring on the housing.

I would jack the car up on the drivers side, or the rear would probably work just the same to keep the ATF out from where you'll be working. The speedo setup is very easy, however if you dont have a book or have never 'clocked' your speedometer gear, put a sharpie mark or something on the housing and the case so you can line it up easier without having to count the teeth on the gear and all that fun stuff.

Should just be able to jack it up, probably dont even have to take the cable off the housing, just remove the (i think) 7/16ths bolt that is just like a distributor hold-down, you can wiggle your speedo housing out after that is off. Then using a pick, might be able to just get it off with your hand, take the o-ring out and put a new one in..should be that simple. If you dont have a o-ring taking the old one to a napa, carquest, etc, etc...they should have one the same size.

Very simple job.