Ok 40% of the time I shift into 5th it grinds. Especially if I am getting on it a litle but. Well the other day I was on the highway doing something I know I shouldn't have been but tere was this WRX STI trying to race me so I thought I would let him know what my lil car could do. I had him by a car and a half at 120mph but 5th gear started grinding real bad and then even when I put it in neautral it was still vioently shaking and going haywire. The car still drive fine and I tried again to take her up but agian at about 120 its shakes and grinds. Any suggestions? What the heck is wrong?