A few weeks back I mentionaed that I thought I was having diff problems after having both wheel bearings changed since the garage who changed the problems could find no other problems. The bearings of course did indeed need replacing intitally but after a few hundred miles the front end noise had returned. The symptoms( drumming and whining noise on turn in) pointed to wheel bearings still but a few visits to the repairing garage with more wheel bearing changes under warranty convinced me that it was not the bearings. The recommendation from some I believe was to check out the inner CV joints as it was rare for an auto trans v6 model to have a diff problem. Glad to say it was not the diff and after changing both half shafts at a reasonable $100 CDN a side it was not those either. The noise at 60 KPH was huge. Well it turned out to be one of my Michelin XGT-H4 tires ( 4 mm tread left) that was causing all the noise and I have to thank a Ford tech for quickly diagnosing it. It was not like any kind of normal tire noise that I have heard before as it started off a low cyclic rumble from 5 KPH building to a 95 100 decibal drumming at 5 KPH with considerable variation with steering changes at any speed. Then from 60 to 80 KPH the noise would virtually disappear and resume as an increasing bearing like whine up through 120 and beyond. It came from all over front drive train but steering to the right made it seem as if bearing was making noise and touching the brakes lightly increased the noise output.
Moving the one tire to the back quickly illustrated the problem since all the noise transfered to the back. Likely there is a structural default in the tire since it looks ok but with considerable wear on the tire it could be that as well with harmonics building up with speed (they are sort of like a resonating chamber).
The lesson here to my chagrin is that rotating tires a few times in a known pattern may help quickly eliminate the mechanical components in the drive train as the culprits with front end noise and save time and money. Hope this helps some.
P.S. Had to replace the impeller side of water pump as the plastic impeller detonated last week. 2.5 hours of my labor and replacing all of the stupid OEM spring loaded clamps with all SS screw ones and I was back on road with no bad side affects. Of course I was anticipating it to happen for some time so I noticed the high engine temp immediately and stopped right away to be towed home.