Actually that's not quite how an auto hub works. When you are in two wheel drive, you are not spinning the cv's.

The only time you would be spinning the cv's is if you are in 4wd. But, when you shift back into 2wd you have to back up a short distance to "unlock" the hubs. If you do not do this step you will spin your cv's until you do reverse direction enough for them to unlock.

So really there is no real wear and tear on your cv's on everyday driving with the auto hubs.

The only trucks that have wear in 2wd, are the 98 and up Zu's. They have drive flanges that directly attach the cv joints to the wheels. This configuration will have your cv's spinning in 2wd or 4wd.

Joe