Hi, first time posting. In the last week when I am accerating from 21 to 45 MPH, there is a slight vibration bumpiness/hesitation going on. Not every time but most of the time and only at those speeds. No check engine light or any dashboard light are on. Took it to 2 transmission places and they stated to take it to a mechanic who could see if it's something with the engine misfiring or similar before they'd want to tackle the transmission or if it is the torque converter. No other issues with the car at all, no steering wheel vibration or internal parts vibrating. It just turned 96K . Any thoughts?