Gear noise

It is not a new build, and not one that I did. It is a narrow Dana 60 with a I think a Powertrax sure grip. The gears were changed before I got the car, and since I have it , has always made the wining noise on acceleration. This winter I will pull the cover and check the pattern and backlash. All the rears that I have set up, I have never ran into this issue before. I would hope that new bearings were installed with the new gears, but not positive. The u joints and yoke feel ok .