Location of Drain Plug for Transmission

I am trying to drain the transmission oil out and replace it as specified once a year, but I can't find where to do it. 1996 Ski Nautique Ford PCM GT-40 with PCM 1:23:1 transmission. The manual says "using a 7mm allen wrench" and the drain plug is "located in the transmission adapter housing."
The picture in the manual looks like a flat piece of steel with an allen wrench opening...this picture could have been taken on an aircraft carrier for all I know...it doesn't show or mention position in the engine or location....
I can't find this for the life of me. If anyone has a pic or can capture one on their phone I would be grateful.


I also have Topsider pump that I use to extract the engine oil. I have read also in the manuals that I can use this to extract the Transmission Oil through the dipstick hole? Or from somewhere else?

First: Love the boat. Teal and black color scheme is the same as I have.

Second: fluid extractor is a good way to change transmission fluid. Leave the 7mm hex hey in the toolbox. Some will add some copper tubing as an extension to get all the way down inside the transmission. Remember that these transmissions are sensitive to fluid volume. No need for synthetic fluid Dex/Merc is fine.

JQ

I use a used plastic pump from a shampoo bottle, it worked like a charm. I thoroughly soaked and removed all shampoo residue prior to placing into the dipstick opening. I removed almost exactly 2qts. The transmission fluid was out and new fluid in in under 10 minutes..