Do this test...
open washer door and grab the top edge of the inner wash basket
push straight up on the basket while steadying the outer drum with your other hand
is there any lateral movement? Or is it tight and secure?
hope for the latter, because the former is the telltale sign of a worn bearing, a broken support spider or both...not worth repair if this is the case.
If all is good here, go around back and take off the cover. Look for a loose pulley on the basket shaft.
of course the counterweights could be loose but you don't need me to tell you how to check this.
Source: Making A Rukus During Spin Cycle - GE WCVH6260FWW