Chuck S

Pull the differential oil and have it analyzed. Blackstone Labs can do it easily, just email them for a free sample bottle to fill and send it back. I admit to not doing this (for the differential) as my car shows none of your symptoms. A good full synthetic hypoid gear oil is essential. I've been using LE1605 which is highly regarded here. Run the car a couple thousand mines and pull a new sample for analysis.

-- Chuck

Bruunz

I'm not in the US, but i'll look around locally for oil analysis. I don't think i can get LE oil in Australia either (that would make it feasible).

I've only done one track day since the new oil has gone into the diff and probably no more than 1K KMs. I haven't driven the car much of late.
I'll try and get a few track days in and some more mileage done. I'll let you know how i go in the new year.

I appreciate the feedback.