I bought my MY00 a little over a year ago with 18k miles on the odo. From the first day of ownership, i have always heard/felt what i thought to be the famous clutch "buzz decel" noise as i only experienced this during decel when i am off the gas. Last summer, i drained and replaced the OEM diff fluid with Mobil 1 75W-90 gear oil. The OEM diff fluid that was drained was pretty nasty but from my readings, this appears to be normal. There was no change to the "decel buzz". This summer, the car now has 20k miles (yeah, garage queen) and i figured it will be a good idea to do the diff again since it was pretty nasty the last time i drained it. What i found this year was, again, the fluid being pretty nasty! It clearly had silver particles in it and the fluid was greyish! I figured with so little mileage between change (around 2k miles), the fluid will almost come out clean/clear. In any case, i siwtched up to Amsoil 75W-110 heavy duty gear oil this time around. On my test drive, i noticed the car driving smoother and the clutch decel/buzz noise has mostly dissappeared. This leads me to beleive that it was the diff making the previous noise before. Has anyone else experienced this? Or is it the weed i am smoking?

Thanks.

 

Sad to say I think you have an issue with your diff. I have used Mobil1 75w90 on countless s2ks for the last 7 years. Even after 40k miles, and even on my car which gets drifted regularly, the fluid comes out like brand new. Fuzz on the magnet is almost non existent.