the sound that I fixed was a "clunk" that I always get everytime I accelerate from a stop and let off the gas, it would make a clunk noise which I always thought it was from my drive shafts. I got under the car and checked the driveshafts, cv joints and every motor/tranny mount there is and everything looked normal until I was looking at my Y-pipe and finally saw that my rear o2 sensor was against a piece of sheet metal ehich caused the noise everytime the engine torques during acceleration. It has been hitting eachother for about a year and it even wore a groove on the plastic of the o2 sensor and sheetmetal. simple fix- bend the sheetmetal out of the way and no more clunk may not be much but this noise was bothering me for a long time and was worrying that it mught be my transmission causing the noise.