I tried the magnet. I just started to mow the perimeter of my yard. No luck. I think it is a aluminum plug/bolt. Picture #1 is a picture I took from the video and it only showed the plug/bolt for a second. I had to rewind several times just to freeze the frame. It doesn’t show any more of the tag. Honda has so many hydrostatic transmissions. The plug/bolt is on the bottom and I haven’t found a diagram that shows the bottom. I’ve checked pictures of online sales of used Honda trans and still no one shows the bottom. I even called Honda power equipment US headquarters and they could only refer to my local Honda repair shop. The same one I purchased my mower.