[skid mark]

Also advised not to use first in the auto as well.That is
why the warning on the dash when it is off.YOU DO NOT
NEED IT.Put in Sport instead.

So you're saying not to use first gear inhibit?

 

[skid mark]

I can only select either Sport or 1st gear inhibit, but not both. The other option is normal mode, which allows 1st gear to operate normally, with no sport shifting. This allows better acceleration when merging into traffic from a full stop.

 

[skid mark]

I drove a 1973 Oldsmobile Cutlass in high school and the diff whine sounded exactly like my DB7's. It's probably just a GM design issue. Now if it was a rear end roaring sound at highway speeds, or constant whine at all times, that would be more concerning.