Okay, let me update this for you. I messaged hydro-gear about this as well. They sent me an email stating that I may have put the charge pump covers on the wrong way. So, I took them off, turned them around, and re-installed them. After that, I did a purge again. And after dis-engaging the by-pass valves I ended up with the same problem that I started off with, less the oil leak. The right drive works perfectly, but the left is not responsive. It never made any out of the ordinary sounds prior to this happening. Matter of fact, it worked perfectly the last time that I used it last year. But when I tried to use it for the first time this year, it was right side working, left side not. Any thoughts? Thank you.