Wierd Noise from Rear end... can't figure it out

[joemayo]

K last saturday night went to track did couple runs and after the solid axle started making a loud huming noise.. It's not the tire switched those out. It does it all speeds faster I go louder it gets.. whenever I'm slowing down it's a wom wom wom wom wom sound I"ve thought wheel bearings or gears.. axle isn't bent already jacked car up and drove it no movement..just pissing me off I can't find the sucker

 

[hurtindude]

gear run out maybe ??? Only think that because it pulses. could be a bearing too i guess...