The design of the balancer prevents the internia ring from slipping,it's like a heavy plate with the pulley and hub rivited to it with rubber discs in between.They all seem to wobble a little,I got one that wobbles and the engine runs smooth.
Sounds be an out of balance clutch assembly or somethin in the engine,a loose flywheel should make a knocking noise when you get on and off the gas,but............just drop the flywheel pan and see if it's loose..
