The other day, I started noticing a new noise out of my truck that sounds kind of like a whistling coming from the back while driving down the highway. Originally I thought it might be the wind in between the canopy and the truck itself, until last night. I was leaving the gym and when my wife pulled out of the parking lot, it happened again, I was in the back with my daughter and had the window rolled down, and I heard it loud and clear. The wife said it also happened at the gas station before she came to pick me up. The truck was only moving at about 5 mph on a turn when it happened.
Could this have anything to do with the sounds I am already hearing out of the rear end? I have a howl coming from the diff between 45-55 mph, only during acceleration, and also the far to common rumble from a take off(clutch packs). Ant help on this would be greatly appreciated.
P.S. My truck is a 2004 Screw Lariat with a little over 88,000 miles on it. Bought it in February and the rear end had to be rebuilt when i got it. It has become apparent that whoever did the job, did not do a very good job at it. Thanks in advance!!

 

Just a quick update, I was sitting in the line at a drive thru today, and everytime i would hit the gas and let off, it would make this noise. I dont know if it is coming from the differential, but it almost sounds like metal on metal friction that makes a high pitch squeel. Any ideas??

 

Another update. As it has been getting warmer out, I took my truck and washed it really good, but before, i double checked all of the lug nuts to make sure they were tight. After I did all of this, the sound went away for a couple of days, but now is slowly starting to come back. Cant tell where exactly it is coming from due to the fact that, everytime i try to recreate the noise, she doesnt want to perform for me, lol. If this helps anyone with some ideas please feel free to share them, Thanks!!