I bought a 2012 Prius with about 160,000 miles a few months ago. I have already put 10,000 miles on it (bought it because I have a hardcore 95 mile commute each way) There is some kind of modulating whine that first becomes audible at maybe 58 mph, peaks at about 63 mph, and is gone by 70 mph. At 60 and 65 it is loud enough to be equal or maybe slightly louder than the tire, wind, and engine sounds. At first I thought it was a wheel bearing, but I hear nothing at slower speeds or higher speeds. I have already changed the tires and changed the transmission fluid. I am thinking it is a semi-normal sound for a high mileage car that is either a differential sound or something from MG2. I think this because it seems to be coming from right below my feet, which is why i initially suspected a left front wheel bearing. I cannot get a clear recording of the sound yet, but I had an old car that had a rear end whine at a narrow range of speeds and it reminds me of that. It has not gotten any different over the 10,000 miles, it is not louder when there is a lateral load going around a curve, and it does not change volume as I accelerate or coast. Anyone able to confirm my suspicion with that limited amount of information? Possibly also relevant, I noticed that my MG2 temperature gets as hot as maybe 190F going up extended grades (6% for about 8 miles, with maybe a half mile of level road near the middle) Data was taken from Torque Pro and the OBDlink LX module. I appreciate any stabs at this one.
I see those temps on MG2 in the city during summer, or extended high speed driving. That's not too hot and surprisingly low for pulling the grade I think you're talking about.
Going to need a New Trani........ Change fluid now! look for metal parts........ it will only get worse.......
I ran the tires the vehicle was sold with for about 8000 miles til one had a blister, and I was down to 4/32ths anyway. On brand new tires of a different manufacturer with no change. Wheel bearing I could believe, but I have never had one that was very speed specific like this. Not that it rules it out, but there is no discernible play when I jack up the front and wiggle on the wheels, and no obvious roughness in rotation. I have an infrared thermometer, I may compare hub temperatures after running at sped for a while (with a minimal braking stop to avoid confusing the issue)
