Walk-Behind Mowers

I purchased a poulan lawn mover model PR25Y22RKP 3 years ago, and the rear wheel broke off this past weekend. I noticed the other side is also cracked and ready to come off. The plastic splines on the inside of the wheel assembly must become weak after a period of time. I noticed on the internet that this has happened to other user with the same model. I know this mover is out of warranty by a year, but this seems to me to be a design flaw. I had a Lawn Boy prior to this mower for 10 years and had no problems. Will the company stand behind this issue, and send me two replacement wheel assembly #408852X421? If not I would be very disappointed, since I take care of my mowers, and now this was not from abuse.
Regards