I have a 1992 Rodeo, when I go to like 60mph it stops accelerating and if I press the petal to the metal it just sounds like I'm reving it in park so I was wondering if I needed a new transmission or could it be something else thats alot cheaper to fix?

sounds like your clutch paks need to be replaced. Inside the tranny! or maybe a pressure seal. i would first check you AT fluid level, make sure you let it heat up and check while the car is running.