I noticed over the weekend that the power steering on my 05' F250 seems to be getting a little weak. When I was backing up to my camper trying to hook it up, and tried cranking the wheel over a few times without the truck moving, it barely wanted to move. As long as I'm rolling a little bit I'm fine, but if I'm sitting still......after a turn or two off of center, it doesn't want to budge.I'm not very familiar with how the power steering systems for these things......any ideas on troubleshooting would be great! I took a quick look under the hood and didn't see a power steering pump or reservoir...does it run off of the brake fluid reservoir?