Front end whirring noise - not wheel hubs?

[Will1657]

Hello,

2006 S80, AWD - 150,000 miles.

I've been noticing a very dull humming noise that appears to come from the front end. It's fairly faint - sounds similar to tire noise - but it's a new sound. It correlates with wheel speed, not engine speed. Higher pitched at higher speeds, but still faint, almost like wind or engine noise, but on a noticeably different frequency. No vibration or impact to ride that I can notice - yet anyhow.

I suspected wheel hub bearings, so I jacked up the front end and gave it the "wiggle" test on each wheel. I didn't feel any looseness. When rotating one side forward and allowing the opposite to counter-rotate, I can hear some noise but it's hard to tell exactly what I'm hearing. I took turns blocking one side and rotating the other tire only and vice versa. On BOTH sides, I could hear sort of a rubbing noise, that increased to a dull whine with speed. The whine was patterned like 1 squeak/whine per rotation. I also occasionally could hear what I think of as the typical failed bearing noise, a sort of random clinking that gets more frequent at faster rotations. The clinking noise was not patterned, i.e. it wasn't rhythmic, it wasn't exactly X clicks, per revolution, but it was more frequent at higher speed.

Are there any bearings in there that could be going bad that would make noise regardless of which tire was being rotated (LH or RH)? While driving, I notice the sound driving both straight and while turning, but only over 25 mph or so. The bevel gear unit was replaced by my mechanic with one from a junk yard about 5000 miles ago. What's my next step in diagnosis? Get it on jack stands, drop the splash guard and see if I can pinpoint the location? Are there certain seals I should be checking? Or checking oil level in the bevel gear housing?

Thank you very much fellas.

Regards,
Will

[ThomasKent]

There is a support bearing for the passenger side drive axle. If it`s not the hubs it could this bearing since it rotates with tire speed. I had the driveshaft center support bearing make noise on my old 240.


Part #3 It doesn`t appear as if you can buy the bearing separate from the shaft
http://www.tascaparts.com/auto-parts/20 ... oints-scat

[ThommyKent]

There is a support bearing for the passenger side drive axle. If it`s not the hubs it could this bearing since it rotates with tire speed. I had the driveshaft center support bearing make noise on my old 240.


Part #3 It doesn`t appear as if you can buy the bearing separate from the shaft
http://www.tascaparts.com/auto-parts/20 ... oints-scat

[Legofan]

My dad just had his AWD serviced for the same reason, it was the wheel bearing/hub on both sides as well as the ABS tone ring on the driver side. If it's determined by wheel speed it's one of those two things, hubs or CV shafts.

https://www.fcpeuro.com/products/volvo- ... opt-891878

http://www.rockauto.com/en/catalog/volv ... embly,2288

[ThommyKent]

My dad just had his AWD serviced for the same reason, it was the wheel bearing/hub on both sides as well as the ABS tone ring on the driver side. If it's determined by wheel speed it's one of those two things, hubs or CV shafts.

Or the passenger side driveshaft support bearing.