Yesterday night I drove out to my brothers house in L.A which is about 15-20 minutes from here. I was parking my car in front of his house and as I was going Reverse I hear this Noise kinda sounded like metal touching or rubbing coming from the right back end of my car. It was wierd cuz i never heard this before. I chilled there for about 3 hours then i went home. The drive home was fine, But as i got to the front of my house there it goes again, it feels as if it comes after 20 minutes of driving and when i Reverse and Also when i turn slightly, like when im parking. I got no idea what this problem is. It also does it as i go foward slowly. Any Help? Somone suggested to check my U-Joints.

 

That really sounds like the rear end is going out. If you can afford it, now might be a good time for a limited slip SLP Torsen for 99, and a new set of gears lik 3.42's which you can generally find pretty cheap off of the boards, since they came in every 94 and up M6's, and many of them go to 3.73's, they usually sell them...But I'd get underthere and look, maybe pull off the rear end cover and check the magnet on the lid, and look inside the casing for loose metal and or cracks. It's probably a good time to change the fluid, anyway. I use 85w-95 gear oil made by Redline. I still add the required amount of GM Limited Slip additive to it as well. A Chilton's guide or Haynes manual will have the directions for fluid draining.