So after numerous rebuilds ( messing with the backlash, putting used gears, putting another set of new frpp gears), noise is still there. I will post pics of the the original gears i bought from AM (hopefully tomorrow). the pattern seems fine but a second opinions is welcome. At this point i am thinking it could the bearings. when i bought the bearing kit i forgot to buy the AM specified inner bearing. I asked the shop to supply it for me. I double checked with them if they knew about the inner bearing change from 09 to 10+ models and the owner was aware of it. The inner bearing they used is a timken m802048.
Again the noise is very faint, i can barely hear it on accel (mostly due to loud exhaust),decel (50-0) and coast(especially around 50-65).