I've been a member for a while, but generally post in the Deere and Ford forums about my Deere 2210 and Ford LGT145. I've owned my CC for a little less than 5 years, when I bought it new because my wife didn't like mowing with the LGT.
It has been a good little tractor for 4.5 years, mowing the lawn and pulling the sprayer, but I noticed a couple of days ago that it was leaving a puddle underneath the transmission. Small, but when they don't have a lot of fluid in them, a small puddle is a big deal.
I looked up the part number on Cub looking for parts (seals, gaskets, whatnot) and was only given a part number for the entire transmission. I called my local servicing dealer this morning to be told "yeah, they really aren't repairable, most people just drive them until they die and then buy a new mower". I don't mind telling you all, I was a bit perturbed with the idea that my $2,700 mower with 4.5 years and 109 hours under its belt is just about ready to be parted out. I looked around at a few different sites, all just giving me a part number for the entire transaxle. I finally decide to check Messicks (God I love that site) and they gave me a manufacturer and model number for it. Hydro-Gear 311-0510. So naturally I headed on over to the Hydro-Gear website and wouldn't you know it, they have an entire SERVICE MANUAL for this "unserviceable" transmission! Now, they list it as a 310-0510, but when I reached out to Hydro-gear support people they let me know that it is the same service manual. BTW - Here's the website for their manuals: https://www.hydro-gear.com/service-and-repair-manuals/
So, after digging around and watching a few videos about how I might be able to add a little fluid at a time until either the leak gets bad enough that I have to fix it, or I put it away for the winter, decided to go looking for the transaxle fill port. Yep, that's in a pretty tough spot. Really need to drop the transaxle to get to it, unless of course you raise the seat, pull out the battery and lift the battery box out (no tools required) and then you can look right at the fill port straight. See attached picture. It's an allen head screw (looks round in the pic).
So while no, you can't simply pull a plug, drain the transmission, swap out a filter, and fill it back up, these can be serviced and you can buy parts to fix them. Here I was ready to throw $750 at a new transaxle when it completely ran out of fluid, but I think I can keep it going until I get the time to pull it out and replace a couple of seals.