I had problems with my gears, and found this gear speciality shop in Anaheim. They are awesome. My gears are just right now... no noise at all! The GM is named Devin King, and Scott Zapper did my gears. You can call Devin to ask questions... He'll blow you away with his knowledge. He has quite a name in the Viper community for custom drive shafts. About $350 for labor on a gear swap.
Unitrax: King of Gears
Also... Differentials, Drivelines, Overdrives, Axle Shafts
1280 N Sunshine Way
Anaheim, California 92806-1746