The right upright on the loader frame is the hydraulic reservoir. It holds 5 quarts.
I looked at the one still on eBay with a BH, but it seems much more used and abused. The one I bought was closing a few days earlier, so I decided to for it. I'm glad I did, since the one on eBay is $6100, with over an hour left, and the reserve still not met... The one I bought was a "no reserve" and I got a chance to talk with the seller on the phone before bidding.
Mine has primarily been used to plow/move snow, and kept inside. So, even though it has quite a few hours, I'm sure, it still hasn't been "used and abused" on a construction site.