I've found a lot of information about this same issue across the Web. I agree that this should be a recall issue for Hyundai. I have owned several cars and driven more than one far past 100,000 miles with no steering issues. (GMC, Ford, Honda, Nissan) Hyundai should replace this coupling with a higher quality rubber. There is a recall involving the airbag and seat belt tensioners. While your in there... replace the damn coupling!

I thought the rattling I was hearing was from the wheel. My mechanic checked it out yesterday and advised it was the steering column that was rattling.

Steering wheel is clanking and rattling a lot. It's very loud and clanks with every slight turn of the steering wheel and even worse when I hit a bump in the road.

there is a clunk in my stering wheel and a rattle

Apparently the coupler in the steering column is an issue with the 2012 Hyundai Sonata according to Hyundai service. I would certainly think that if Hyundai knows this is a problem they would have an extended warranty or recall for this coupler replacement.