I've been asked to take a look a a friend's Cub Cadet riding mower. Apparently, it will chug when you press on the reverse throttle. I checked it out, and found a lot of grass and dirt packed behind the reverse plate. I cleared that out. It now goes into reverse, however, I noticed a leak from the left side of the transmission (see attached photos). I can get to the fill plug, but am not sure what type of transmission fluid to use, how much to use, and how to plug the leak. I'm assuming that I'll have to pull the wheel. Is there a seal or something similar on each side of the transmission? I apologize for the lack of specifics, but I ran out of time. I'll be taking another look at it later this week. Any suggestions? Thanks, in advance, for the help.