Changed serpentine belt and now getting a lot of noise from the area. Narrowed it down tonight to the area circled here. The lighter grey area was bouncing all over the place, only while in reverse or drive. Is this part of the power steering pump?
I just changed my serpentine belt as well. I spun the tensioner pulley when the belt was off and found that its bearings are kind of growly. So now I'm getting ready to replace the tensioner as well.. which I suppose I should have done in the first place.
Did you check your tensioner pulley when you had the belt off?
I've only had to change the tensioner pulleys since the bearings do wear out over time. The tensioner itself should probably be OK still, as it took a bit of muscle to release the tension.
You'll need to remove the tensioner from the engine to replace the pulley, only because the bolt that holds the pulley on is held on by a nut from behind, and that nut may fall into the engine when it loosens. There is no way to reach around behind and put the nut back in--not enough room. It's an easy job though--the engine mount comes right off (support the engine with a floor jack and a wood 2x4 on the oil pan), and gives all sorts of room for activities. And also makes the belt way easier to remove and replace.
It's best to get the engine mount out of the way, the belt off, and see which parts of the tensioner might be loose. The pulley is a wear item, so a badly worn bearing could cause it to rattle or move. But if the tensioner somehow got damaged, that could be a possibility also. If the spring were broken, your belt would probably be slipping quite a bit.
The tensioner assembly is very easy to remove--it's only three bolts, plus a fourth bolt that holds the pulley onto the tensioner. The engine mount isn't that much work either--it has mostly 17mm and 19mm bolts/nuts. Removing it frees up a lot of room to inspect what you have going on. And it makes removing and reinstalling the belt way easier.
Agree with Wildcat. Pulling on the bolt to release enough tension to slip the belt off is actually tightening that bolt. So it is probably time to change the pulley or the entire tensioner. Some sites say to change the tensioner with every belt change. Some every 3 belts. Whatever. The pulley is a wear item.