Neighbors 05 does the same deal once in a while.Bet a valve body issue.Shift solonoid(elect) or what not.He's got 90k on his and its once in a blue moon towing 9k or so on long trips.He's never really has had his ever looked at.

 

Well, it's either A or B solonoid is not functioning, one because either might be caput, or it's not getting the signal from the computer, which maybe because of a faulty speed sensor on either the input shaft, or output shaft possibly. It's hard to say until the put a scanner on it, and manually force the solonoids to activate, it they do, then their not getting a signal from the puter, probably because of a bad input sensor.