[tfoti]

you have to take the speedometer gear out and fill it through that hole. i guess you could follow the speedo cable from the firewall down to it. that will at least show you where it is. i had to get at it from underneath the car to remove the speedo gear. there should also be a retaining clip that holds the cable in place. oh, and be careful when you remove the cable and putting it back in. if you pull too hard the other end of the cable will come out of the instrument panel making your speedometer not work (at least thats what happened to me). to check the level of the fluid you have to insert the gear back in take it out and look at the gear. make sure that there is enough fluid to go almost to the top of the gear.
i hope this all makes sense!