No drain plug. Filter is located inside the transmission pan on the bottom of the tranny.
bad torque converter .
I'd say "not likely". While it's possible that a torque converter is out of balance enough to cause a vibration, in general that's not the case unless it has been hit or damaged in some other way. It might be better to talk to someone who knows what he is talking about.
A bad torque converter can cause slipping gears. The fuel mileage will suffer as well, and the engine will rev higher.
No, it will not cause the engine to knock.
Torque converter lock-up solenoid is bad. Common problem with 1988 Beretta.
Yes.
torque converter can cause this. you will have bucking and stalling. another thing it can be ( I know this to be true as it happened to me) is the cat converter.
Loose converter bolts or a cracked pressure plate.
Yes there are.
loose or missing torque converter bolt to the flywheel
Either the solenoid pack or most likely the torque converter itself.
big job you have to remove trans or at least back it out enough to remove torque converter cause its behind it