I have searched high and low for info on the front diff. No luck. I would even consider rebuilding one myself but cant seem to find parts for it. Other than dealer. I found a Zf logo on it and contacted them, no luck , even went the Vw way. Vertex in Miami will rebuild it for 1900 plus shipping with me doing the swap of the diff. the price range used to new is 1200 to 2500. Seems like the front diff on these vehicles are issues that Porsche won't admit to. I've owned around 38 vehicles so far in my life from full size diesel trucks to Audi quatros. My 04 cayenne was a one owner car up to 48000 miles, I now have 96000 miles on it and my front diff makes so much noise I don't trust driving it.