Went on a long camping trip this weekend and on the way back I kept having an intermittent loud whine that seemed to vary with the engine speed, not the vehicle speed (it was even present when the truck was stopped and in park.) It did it when we left camp (everything cold) and eventually stopped on its own. It would periodically come back but never as loud as when it first started. Since I've had transmission problems before (had the 4L60 rebuilt in 2016 after it failed on the way home from a camping trip) I assumed the sound was from the transmission, since it seemed to vary based on speed. Then, this morning on the way to work it started making a really loud noise, again a high-pitched whine. I noticed the sound "spiked" when I turned the steering wheel sharply which now leads me to believe it might be the power steering pump. Not sure if I can upload the video file of the noise but I'll try. Anyone else have a similar problem? Vehicle is a 2004 Suburban 1500 LT, 5.3, 4x4, with about 175,000 miles on it. Transmission was rebuilt at 150k by a reputable shop. Thanks in advance for any advice or pointers! EDIT: Can't seem to load the *.MOV file from my iPhone. Is there any other way to upload a video? File is 20mb if that makes a difference.