Aode heading to the grave?

My dad called me since he is driving my car back from jax to Miami. He says the car had a little burp while driving. The rpms reved up to about 4k then he let his foot off the gas and they dropped back and all was ok. Now he called again saying it's happening more and more and he did check the tranny fluid and it was ok. Could it be it's just running too hot to function properly? Could it be the tq converter or is the aode on a car with very low miles about to die

Thanks, it was happening on the highway. He eventualy started to pull over and let it cool down for a little bit. He said after he started doing that it went away, also the temps outside dropped as night came and it started to rain. I guess I may replace the converter first and hope it goes away for good. Or I may try throwing in a valve body and tranny cooler first, not sure which.