About a week ago my brother was driving my 2000 firebird 3.8 when he noticed the rpms really high up and the car didn’t want to shift into gear instead of shifting at 10mph it would shift it around 30mph while making a power drill noise and grinding noises once he got home he tried reverse and it didn’t work too but after 3rd gear it would be shifting fine and no more noise but the RPMs were still a little high any help? Also I checked the oil and it seems fine In the meter