is it in 4wd when this happens ??, have you checked your diff grease ???
the reason i ask this is i had a leaky axle seal up front and when it would get low it would roar....i would add too and it would stop,,,,
just trying to think ,im still on my first cup of coffee---lol
4inch suspension lift,3inch body lift,4.0 5 speed,8.8 with disc,s,16inch moto metal rims ,and some 35s..
with trail rash..and getting 25mpg,s