My Kenmore washer started making grinding noises during the wash/rinse cycles. Spin still works, water fills and drains properly. I noticed that when it started grinding, nothing was actually moving inside the washer. To get it running again, I have to open the lid, move the agitator around, close the lid, and repeat this from 1 to 20 times until it finally clicks back into place and starts working again.

I took the front off to see what's going on in there. The belt spins good and appears to be in working order. The big part above the belt is what stops moving when the grinding starts. Here's an upsidedown video of what it looks/sounds like...

https://www.youtube.com/watch?v=_MJd55y1t2U

I figure it has to be a gear somewhere that needs replacing, but where? And is it an easy/cheap job, or difficult/expensive one?