Whirlpool 3RLSQ8000JQ

Since fitting a plastic, tub drive coupling and a pump to this machine, the customer says it washes and rinses okay, but when it spins its okay at slow speeds but as speed increases it starts to vibrate badly, it even does it with no load in it, i thought it might be a silver susp spring that is on the rear bracket as i wasnt sure where it came off when i unscrewed the bracket i clipped it onto the only slot i could find on the lower back panel, does anybody know where this locates, i was also wondering if the friction pads may be damaged by the amount off water that was peeing out of it, any help woud be most welcome on this one cheers JJ