Rear ends going??

[rkh3]

What are the indicators that one is going bad?
My car (only owned it 3 weeks) has 67k on it and there is a noise, kind of a whiring (not whining) noise loudest around 40 mph from the rear. Nothing till 35 and not much after, ok in hwy, only slight. Just had new tires installed and it seems louder but does not change with road surfaces. Car has been lowered if that matters. No other symptoms. Anything to worry (I do that a lot) about?

[sunsetorangess]

You can jack up the rear of the car and put it in neutral and turn the tires by hand to pin point where the noise is coming from. Check the fluid level and condition in the rear.
U-Joints are common to fail, Depending on what suspension the previous owner did could just be transmitting road noise. You said that it seems louder with new tires so it could be just that, some tires are noisey. Are they stock gears in the rear? Aftermarket gears tend to be a tad noisey also.

J

[rkh3]

Really unlike me but I do not have much, just carfax, history on the car. Po just said it was lowered, that is obvious. Car is too low to get under. Would make sense that if you are going to the effort and expense to lower it you would do ther work as well, like changing rr gears.

[cammed goat]

Are you getting a vibration while driving along with the whirring noise?

[rkh3]

No vibration.

[Cutlass]

theoretically they are supposed to be very quiet. In reality, a bit of noise is normal or ok. Loud noises aren't ok. Suspension mods like poly bushings tend to transmit more noise then the factory rubber so take that into consideration

[rkh3]

Having my mechanic check it out Thursday, probably nothing but I want to make sure.