Nah....not through the filler or you will be there next Xmas !
Under car....undo and remove fill plug up the passengers side of the tranny..... then remove drain plug from under the transmision.
CATCH OIL of course but not in your hands
Clean drain plug of crud...fit new CRUSH WASHER ! ! !
Refit.
Get a cheapo pump....I got mine on
www.screwfix.com and refill till it trickles out filler hole.
Refit funny square headed bolt again.
Job done.
NOTE: Easier if oil is warm and do not...repeat DO NOT do it under the car on the car jack ! !
Axle stands are the order of the day OR a pit...or a ramp.
Better if the vehicle canm be kept level but NOT critical.
GOOD LUCK 