I have a commercial size direct drive Whirlpool washer that wont spin but it does agitate. If you give the tub a 'jump start' by trying to spin it with my hand, its starts spinning slowly and continues to do so for like 5 seconds and then it stops. I have replaced the entire clutch and know that is good. ALso I can see the clutch spinning when the washer is supposed to be spinning.

Last night I took the spanner nut off. I ran the washer again and it wouldnt spin until I lifted the inner tub off the drive block, but when i put the tub back down it just stopped. It seems that theres too much weight and the clutch slips. (This is with an empty tub). I havent taken the tub out competely yet, should i do that next?

I found a long sock wedged in between the basket and the tub when I lifted the basket. Now it runs perfect