hi guys i have a 2001 ford truck and it makes a growling sound when i am turning right but is not when going straight ahead wondering what part in the rear end could be making this sound

 

If you have a limited slip axle, the clutches are chattering.

 

Is it like a re-re-re-re-re-re sound? I just replaced the clutch packs and spider gear in my 03 supercrew and had that problem. I had to add more friction modifier to get it to go away. It is the spider gears and clutches turning. Only Does it on turns. If you have recently changed the rear end fluid and didn't put friction modifier in that is your problem.