Is it normal for Maxima's power steering pumps to go bad? I have a 97 SE with about 51,000 miles on it. Today due to a whining noise coming from under the hood, I took it to the local shop to isolate the noise. They advised me that the noise is coming from the power steering pump and will need to be replaced. Now here is the kicker, the pump alone cost $450, plus labor $160 and new fluid, tax will cost me a grand total of about $700 dollars!!! Is this correct or are they taking me for a ride? Also, if the shop is correct in diagnosing the problem shouldn't I feel a heaver steer? Well this is not the case. I can't notice anything different about my car, except for the annoying whining noise. Any suggestions on what I could do?

Thanks in advance!