On my "hog", there's a check plug about 1/3 to 1/2 way up one side and a vent on the top. For filling, the vent is the easiest to use. Just fill from there but with the lower plug removed.

For suctioning oil or brake fluid, I use a MiniVac. You can also get something like a Pela extractor that many use to remove motor oil on vehicles that have a bottom shield in place. I've gonna get one to remove oil from my generator because I made a mess the one and only time I drained it out onto the ground (no way to get anything under it). Will need it later to change the oil on our VW TDI after the 3 years' worth of free service is run out.

If none of your seals are leaking now, doubt you did any damage.

Ralph