Ok, wife's car, 65K , shares same platform as the 40 and 50 / 60 Volvo series cards I think.
Humming noise getting louder in past 6 months. I bet front wheel bearings and planned them some day, well then BOTH axle boots split between oil changes and spewed grease, ok, do new high quality GNK axles and SKF bearings(OEM), at same time.
No real change!
Ok must be tire noise, 25K on tires, did rotate again, no change, ok, screw it, new tires, no change!
Back wheel bearings feel fine, but will do them this weekend.
If this fails what next!. GRRRR