Ok thanks for that info. Here's a video I took of it while overfull and squealing. It almost acts like it wants to slightly die sometimes. The engine starts fine and idles fine. https://www.youtube.com/watch?v=j1nVIInauEQ
No leaks that I could tell. It's a 2013 and no error messages were popping up. Way too much hydraulic overfill wouldn't cause a noticeable difference in the E42's operation? No noise or struggle moving? It was way overfull when cold (almost the whole site glass).
I've been looking at a used E42 trachoe. I'm on the fence about whether to buy it or not. Everything is tight, it has low hours, all actuators are clean, and it starts up easy. However, it squeals sometimes (with no load). Well today I went and looked at it again and checked all the maintenance...