I had that happen on a Chev Suburban one time. The cold was REALLY extreme -50F and the pressure hose blew. I drove it 15 miles or so into a warm shop and repaired the hose. I never had any trouble with the pump. I wouldn't worry about it. It is also fairly common on many PS systems to hear a whine from the pump at full lock. I would bet that it is just fine. Unless it gets really loud or fails to provide power steering there isn't much you can do anyway. If it does fail down the road someday you will just have to replace it.

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1995 G320
1984 280GE
1971 Unimog 416