Technical Automatic Transmission Drain Plug?

[herut]

I can't seem to locate the drain plug on the automatic transmission of my 1998 1.6 petrol. The Fiat Manual refers to a drain plug under the title 'Changing Gearbox Oil', (and it refers to tightening this to a certain torque), but when I look underneath, all I see is a round aluminum colored protrusion set in a recess and held in by a C-clip. What is this? The drain plug? (I doubt it since it is not hex sided for tightening.) Your help greatly appreciated! Thanks

 

[herut]

Anybody??