tranny issues on 91 probe

so i just bought a 91 probe lx with an auto trans, it runs perfect until it hits third, then it just revs real high and goes nowhere for a sec until it catches. it then takes 4000 rpm to get it to go any faster. i was told it could need o whole new tranny. if any of you have some advice post me a message

You are going to need to buy a new one. It happened to my car and I kept driving it when it finally blew and broke both my engine/trans.