OK..so I go to do my first oil change on a B7500 Original owner said it was serviced by dealer just before selling. Has all "K" filters...and he has oil change and services highlighted in his owners manual...so I have no reason to doubt him. Drain the oil....clean and reinstall the plug.....looked like an appropriate amount of oil came out......on to the filter. Filter spun off easily (not too much so).....and no oil.....I mean zero came out. Appears to be no oil in the filter (although the filter felt heavy.....like it normally does. I haven't cut the filter apart.....but that's coming. No issues before the oil change. Any ideas?????