Remove the shifter and pour it in from the top. 

Otherwise I have used a long heater hose with a schedule 40 pipe street elbow clamped to the lower end.  The threads get a grip on the threads in the hole so it won't slide out.  Extend the hose up to the passenger side hood hinge area and stick a funnel in the hose.  Put a drain pan under the tranny.  When fluid runs out the hole, you are done.

I bought a gear lube hand pump at o'reilley's for just a couple of bucks. It does not screw onto the smal lidded oil containers, but the wide mouth ones like mobil1 it screws on just fine. It has a clear plastic tube with a clip on the end that you shove in the fill hole. Pump away and it is full in no time.

BobN

Will these pumps suck thick fluids like 90w from a rear end?

That's a good recommendation from Don.  The Amsoil pump will pump anything including 90W.  I bought one several years ago.