I've been driving my 6.7L (2013 F350 CCSB, 63k miles) since April of this year as my first diesel (and first truck). I've been towing my 10k lb 5th wheel most weekends and things have been going fine. However, last weekend a tractor unexpectedly pulled out in front of me on the highway and I had to slam on my brakes. When he left I tried to get back up to speed as quickly as possible but when I floored it, it sounded...weird. Almost like a wheezy, high pitched whine, sort of "popping" in and out. This was at around 3200rpm for a good 15 seconds. I've never heard anything like this before, though I'm never really able to sustain more than 3k rpm for more than a second or else I'm breaking the speed limit.

I guess I have no idea what these engines are supposed to sound like. I don't seem to have any power issues, so is it just a quirk of what happens when you push the engine hard while towing?