Recently replaced the tub seal and the bearing - which is suggested to do at the same time on our Maytag washer. I cleaned the unit throughly during this repair - the tubs and the housing - all the grease in side.
The belts are both good.
No visible signs of transmission leaking fluid out. And there was not that much to clean inside the unit - little chunks of black grease all around.

There is a problem with the unit starting the agitation cycle. Fills with water fine. The motor runs - sounds like the belt is slipping on the break - typical belt slippage sound.
I can see under the unit with the front panel off. The motor does spin and the belt moves in sync - same on the water pump. Any slipping or binding must be on the break/clutch.
All cycles on the washer do run. How do I know - If I lift the lid to stop the machine during agitation - about 20 or 30 times - eventually it will 'break free' and run normally. After this - I can run several loads through the machine fine. When it sits for several days - this is when the problem reoccurs.
The following process is on an empty washer - no cloths.

May tag washer - belt drive.
Agitator does not move freely if you try to move it in the tub. Good Connection.

When I close the lid the motor starts - you can see the agitator move - 16th of a turn then bind
Lift lid to stop - then close but leave a gap I can see in. This process I repeat.
Sometime I will get one forward and reverse cycle on the agitator and it stops.
Then 2 -4 times no movement.
Then 1 -2 times a pulse and stop.
After a while it starts to agitate but slow. Then there is a squealing sound that will start. Open the lid.
Close - starts to agitate - and the squeal slowly kicks in. Open the lid.
Close - after 2-4 times it starts to run - no belt slippage and no squealing.
At this point the agitation starts to slowly move to speed. Then......machine runs with any problems.

So is this the break or the transmission. Spin has always worked fine. Once the machine 'breaks free' the full cycle of a wash is problem free and the subsequent loads after.