Circa 2000, Sears Model: 110.91521210; Serial: CE3527112.
My wife has complained enough about significant vibration when spinning (with or without a wash load being present), so that I took it upon myself to disassemble the outer cover and study the various tub components. All suspension springs appear to be in place.
To my surprise the item called a "balance ring" is about 2/3 full of liquid (water?) but, upon removal, it shows no signs of internal leakage and the non-removable plug remains tight.
There appear to be no "witness marks" on the balance ring or tub walls, if indeed it is supposed to help balance the tub while spinning, and the ring will rotate on the tub rim with a little urging, despite the many rim clips.
I can find no other component(s) that could interfere with the balance.

Any suggestions from the assembled masses will be sincerely appreciated.

Paul