You say it sounds like it is coming from your roof? Have you checked wind deflecter, sun roof seals, etc? Or it could be something unrelated. Have you checked the fluid level in the differential?

__________________
If it ain't broke take it apart and find out why.

1983 300SD, 4 speed
1994 C280
1987 300TD wagon
1996 HD Road King

Ride in Peace Eric Peterson, Harley of Macon