ghein

I need help BAD!!!! My snowblower is a snow fountain.  The outer ring retainer that holds the discharge chute, broke.  I ordered both a new inner and outer ring retainer and the new parts are BIGGER than the older parts by almost 1/4".  The result is that there is too much "play" with the worm gear and the discharge chute doesn't rotate.  I thought that a new chute collar would have been built to match the size of the ring retainers but NO.  I'm not getting anywhere with sears parts or customer service. anybody out there have any thoughts as to where I might get any help?