New questions on my Maytag washer

Problems:
My 5-year old Maytag (Norge) washer (Model Number MAV6000AWW, single belt) could fill water and agitate, but could not spin or drain out the water. Sometimes the washer stopped after agitation, although I did hear the da-da voice from the control panel, sometimes the washer started to spin but there were some ear-piercing sound and burnt smell and the washer stopped.

Examinations:
I laid the washer down to the front so I could work at the bottom.
(1) Belt: I took off the belt, it had only minimum damage.
(2) Pump: I took the pump out and it was free to turn the pulley both ways with very minor noise noticed, but there was some burnt oil on the pump.
(3) Motor: Without the belt on, the motor pulley turned freely both ways without noise noticed.
(4) Transmission: Without the belt on, the transmission one way was easy to turn and the other way was harder but not very hard to turn

Questions:
(1) During my trials, I often opened the lid and turned to the control dial to some spots then pulled it out. Would this mess up the circle sequence and make some permanent damage? If yes, how to correct it?
(2) Do you think we should replace any part(s) then test again, such as the belt, pump, or even the motor or transmission?
(3) Any other advice?

Thank you very much in advance for you help.

Adam