No loss in power and no idea if turning makes a difference. This would be under load in a straight line...light turns green, mash the gas, RPMs go up, whistle from underneath @3200. Chances are if I was going to turn I'd let off & RPMs would go down = no whistle.
I will add that every now and then it will make a clunk/thud shifting from 2nd to 3rd or 3rd to 4th and sometimes a thud/clunk halfway through a gear. Again it's more noticeable under hard acceleration or while towing. I reported all this to Ford and suggested they were related and said I thought it was the trans making the noise.
In a somewhat related issue, I'm not real pleased with my local Ford dealers and have had repeated issues with a couple of them. This time; brought it there last Wednesday for "the works" and told them about this noise. Said I was leaving it there all day so maybe they could take a look. Called at the end of the day, was told they heard the noise, couldn't figure out the source and wanted to keep it for another day. Went there @ 5 the next day and the truck is sitting outside. Went in, was told they could not figure it out and had a call into Ford corp for help. Took the truck and said I would bring it back the following week as we were headed to New England for the weekend. Got a few miles down the road and realized that not only had they NOT fixed the problem, but also had NOT changed the oil or rotated the tires. WTF!!! So I had to drive 600 miles on what was already an overdue oil change. Not to mention all the "test drives" they did. Frustrating.