Pontiac Repair: Power steering in grand prix., pontiac grand prix, power steering

Question
I own a 1998 pontiac grand prix gt. It has 120,000 miles on it. I just got it back from an oil change and i was driving it when the power steering just quit. I shut it off and checked the reservoir and there was plenty of fluid in it. Also, when the wheel is turned all the way you can hear the pump running. It seems like straight driving fpr a while then one corner allows the steering to work for that one corner then it is back to no power steering. So i have a few questions about this. 1. What is the problem? Is it a pump? Or a clog in a hose? Or something else?2. I live in SD and right now the temp is below freezing. Will this make driving more difficult when the engine is cold without power steering. And 3. How much will this fix cost and how much time will it be in the shop? Thank you for your help.
Max

Answer
sounds like the pinion  bearing inside the gear has failed, you can check with a local dealer to see if your car is involved in a recall for that part.  You may be able to just replace the bearing, if not then the steering gear will need to be replaced