Whining/ humming noise from rear

I’m getting a humming /whining noise comming from the rear of my truck. It happens all the time while moving wether in gear or not. Any advise is helpfull
06 Taco extended cab 4x4 6speed manual.

 

Check pinion and then check wheel bearings

 

Look at the inside of the back wheels. If you see oil, it's the axle seal. At that point, you might as well do the bearing as oil has seeped through the bearing, taking grease along with it.

Good luck.

 

No leaks from anywhere in diff. Noticed drive shaft carrier bearing bushing sagging and slight vibration when in motion. Will replace that and see what we get.

 

I know it had been a couple of years now but what was the outcome?