Alright so I'm new here and to the g body life. I recently acquired my father in laws 84 monte convertible with a 355 small block and a turbo 350 transmission. The issue is when driving around it shifts from 1st to 2nd really high rpm and hard enough to chirp the tires and same from 2nd to 3rd but not as high rpm. The guy he got the transmission from said he had it rebuilt about 3 years ago. What should I start checking to get it to not break my neck when just driving around. Thanks