Background: 2011 Honda CRV 4WD, 145,000 miles, serviced regularly. Since my retirement, most of my trips are local, city-speed and short. In the last 5 months I've made numerous 6 hour trips on an interstate and have noticed a high pitched whine coming from the rear at speeds abopve 60, maybe 55, persistent and clearly not something that was there in the past. I cannot pinpoint the noise coming from a specific rear wheel, left or right. There is little difference in the whine at 60 or 75. There are no grinding noises, or lower-pitched growls at lower speeds, and other than the whine, the vehicle seems to perform normally. Of course I am concerned that this is an indicator something is starting to fail. Any similar experiences out there?

 

When was the last time the fluid in the rear end was changed?

 

Most recently at 107,000 and 142,000.