Hello,
I have a 2000 WS6 and I'm trying to figure out if I have the Auburn or Torsen diff, When I jack the car up and turn one of the tires the other tire turns the opposite direction which I read that a Torsen would do this or a Auburn with bad clutches would also do it?

Is there a way to tell from the RPO codes?

Also if I jack the car up and hold the driveshaft and turn one of the tires I can keep the driveshaft from turning but the tires will still turn, I thought this seemed odd?

Thanks for your help

 

99 through 02 fbodys have the Zexel. I don't know if there was an option to order the Auburn Cone. AFAIK the RPO only indicates gear ratio and nothing I have read tells of brand names.

When my Auburn was going it did not counter rotate the opposite wheel. That you can turn the wheels and not the driveshaft also tells me you have the Zexel Torsen.

If you feel it is time to change gear oil then you can verify what you have while servicing your axle with some new Redline. No springs to be seen with the Torsen, only spider gears are visible in the case window.