Read up on checking the automatic transmissions fluid level. You should check it anyways anytime any form of surging is felt. In your case it is not the issue I suspect. Maybe you have checked it properly already?

There is a tendancy not to check much of anything very often since self serve gas came into play many years ago.

Not all people became neglectful of course. For the younger members information there was a time when far more attention was paid to fluid levels. I am guilty myself by the way of backing off. Just not quite as guilty..