I'm a rookie on this forum. I purchase a brand new 2020 Toyota Tacoma TRD Off-Road. I drove it to San Francisco to attend a function. I was stopped at a red light intersection with the vehicle on an incline street. If anybody been to San Francisco, it so hilly. With my foot on the brake, the light turned green, and as I let off the brake, the vehicle started rolling down, and I heard the gears violently grinding - enough to hear couple of gears or tooth damage. So, I applied the brakes to stop rolling down. I switch to my left foot to apply the brake and the right foot to give it some gas to help not rolling down and was able to turn right onto a flat street. That killed my day to tour the city. Tried to avoid incline hills to go home. So!! What went on? I was able to drive home with no transmission issues. Going to take it to the dealership have it checked out.