[Tommy]

Several years ago I had the good fortune to be invited to the GM test facility near Mesa, AZ. The best part was when I was given one of their Corvettes to drive on the autocross course on their very large skid pad. For a good driver, it was about a two minute course. .... The Corvette I was given was equipped with an automatic transmission. My instructor told me to select Drive and make full use of the car's anti-lock brakes. After each pass on the autocross course, I'd hit the high speed track for a mile or so to cool the brakes and then do it again. During the hour or so I was driving, I never noticed the transmission doing its job. It always seemed to be there in the gear I needed when I pressed the gas. But I wasn't using it for braking.

I agree with the advice to put it in Drive instead of manually shifting. If the brakes need help, solve that problem separately.