Grinding Noise

About a month ago I replaced the steering gear box and power steering pump along with new hoses on my 1988 F-150. Everything worked great until this morning when a loud grinding noise could be heard inside the cab apparently from the power steering pump. The sound only occurs when the steering wheel is turned, however, even the slightest pull on the wheel produces the sound leaving me to believe the new pump is faulty. Am I on the right track or are there other things that could cause this? Is there something I can do to check the pump before pulling it off (as this is incredibly fun on this vehicle, ha).

Thank you for your help.

The power steering fluid was the first thing I checked. It was full. The hoses are metal near the gear box and rubber coming up to the pump with no kinks or even bends. I picked up a new pump on warranty and plan to change it out this weekend unless you think it might be something else.

Also, the sound really isn't a whine as much as a growl or grind. It sounds much more severe than a whine.

Thank you for your input!

Recently, I try to speed up on the freeway and as soon as I am gaining some speed my truck feels as if it's skipping or grinding and I loose the speed. So I let the pedal go and I re- accelarate about 3 to 4 times just to get the speed I need. Each time I do this the same sound accures. Any ideas, I have been told that my tranny is going out.