Listen to driver concern and road test the vehicle, every time.
Vibration, Harshness, and Noise
Always begin at the tires look for uneven wear.
Transmission Vibration and Noise
Transmission and torque converter are not usual culprits for vibration. Check brakes , bearings, joints first.
When it is the culprit, usually it's an unbalanced/poorly mounted torque converter or faulty output shaft.
Should be directly connected to speed and conditions
Any condition with engine running points to the oil pump.
Noises based in a single gears relate to a band or clutch problem.