hey I need help. My Blazer has a problem steering. when I first get in the truck of a morning the steering seems fine even with the rpm's under 1000. But after driving around town for awhile the steering goes to **** (hard to turn) unles the rpm's are above 1200-1500 . really sucks when you are slowing down and down shifting and trying to turn in somewhere. has anybody had this problem or know what it could be??? fluid is full. belt might be a little loose but why does it work when cold and not hot?????