Surging RPMs in higher gears

What is your question?

There us a whirring noise from the engine that sounds like an issue stemming from a belt. Also, this may be untwisted, but when I get into the higher gears around 55-68 mph it jerks a bit and the RPMs surge from 2500 to about 4000ish. My mom has driven it and he encountered that t lower speeds but she juggles the gearshift a bit and it goes away she says. Automatic trans.