We have a 2010 Prius V with 100K miles on it. At about 90 K miles a soft hum started which now is quite loud. It seems to come from the rear wheels. I jacked the rear up and cannot determine that is the problem. To me it seems like it would be the CVT but jacking that front end up I could not determine a problem there either nor with the CVT joints or knucles. The Toyota Garage checked out and first stated they couldn't find the problem but suspect the rear wheel bearings. Another Toyota Tech took it out and states both rear wheel bearings are bad. So I have it scheduled but question that both go bad at the same time. In looking at the chats on the internet I doubt the rear wheel bearings are the problem. Any one able to help me?
Could it be the electric fuel pump? I'm at work now and don't have access to my repair manual files at home, but I believe the fuel pump is located in the gas tank. Might sound like it's coming from the rear area?
I developed a hum too. Right around 45mph it appears and is audible up to about 55 or so. Doesn't sound like it is coming from the rear though; more from the midsection. Started noticing it this sprint. ?
I know this is an old thread and I'm not trying to answer the OP. Just posting my own recent experience with a humming noise from the rear/mid in case anyone stumbled upon this through a search like me. I have a 2008 Prius w/137k miles. Pretty much been rock solid since '08. I've noticed a humming noise coming from the back a year or two ago but only at specific speeds, like 50mph and 60mph plus or minus 1mph. After many months it got louder and expanded to lower mph. I've had problems with a leak in my tire and was constantly airing it up. Finally got the leak fixed. Recently it was pulling to the right real hard. But the front left tire got more worn than the others and was showing metal. Just got 4 new tires today and now the noise in gone. I too thought it was my bearings. Thought they needed to be lubed or something. No more humming noise at any speed, and it turns a lot easier too even though the old tires were aired properly and is not pulling to the right anymore. Maybe I have some slight alignment issue somewhere causing this, or maybe just the low pressure in the tires and the lack of rotation caused this. But it's rolling straight forward and no more hum. Happy camper.
