Anyone out there who knows about KitchenAid stand mixers? I have a tilt-head 5 quart oldie-but-goodie KSM90. I need to replace the baseplate -- if you don't know what that is, you probably shouldn't offer a suggestion. :) I have received the replacement part from KitchenAid customer service (twice!) but I just can't get it in. The old one was tight, but I was able to just drop it back in after taking it out. Any ideas?