Gear whine at 25 and 55

I have an 08 std cab 4cyl automatic. At 25 mph when coasting or with mild acceleration I hear a very annoying apparent gear whine that seems to be coming from the rear end. It happens again between 50 and 60 mph only louder. I dropped it off for service and the tech wrote up "No abnormal noises heard". Is this a Tacoma trait?

 

I would take it back and someone go for a drive to hear the noise Toyota has a new tsb out for just such a noise T-SB-0076-08 the title is Rear Differential Whine or Howling Noise at Highway Speeds dated may 29 2008. Hope that helps

 

I went back and took the tech for a ride (slight upgrade at 53 mph). Parts are on order.

 

it may also be a good idea to drain the factory fill and put in some good stuff like mobil1 75w90 or royal purple severe gear 75w90......awesome lubrication, and probably a bit better than regular 80w90............and it may make the rear end run a bit cooler. just a thought.

 

I had the whine/howl TSB installed in my 08 Reg Cab 4 cyl Tacoma and I still get a slight whine/howl. Service manager says this is normal and occurs in all Tacomas. Should I believe him?