Maytag Frozen Agitator shaft
In the helical transmission you would have to teardown the washer to access the tranny. split the top housing from the tranny and drive the pinion from the agitator shaft, shine it up looking for a binding condition, bearing etc., and use center seal grease in the shaft bearing area when reassembling. install new mounting stem seal kit and possibly tub bearing and reassemble. I have freed up the agitator shaft on the orbital transmission by laying the washer down opening the front cover and transmission cover putting a coffee can to catch the oil when you use the drive pulley to turn the transmission then set washer upright,reverse wires ( not common just fill and agitation circuit) pressure switch to allow agitating with no water and spray carburator cleaner to remove burned on lubricant from the seizing condition in the bearing/shaft area while agitating. It will free up then fill oil back in transmission and replace cover. This has worked for me numerous times with the orbital transmission.