Steering Issue

[Jimjific]

So I have a weird one.

First let me tell you what I have.
- Bone stock 69 SWB Step.
- Power Steering
- Power Drum brakes
- Stock ride height
- 350 A/T

I noticed a while back that every so often my steering felt a little sluggish. I checked the fluid level and all was good. Over the last couple of months it seems to be getting worse. It is very intermittent. I drive 20 miles each way to work with the truck and some days it is perfectly fine (like this morning) and others it seems to have the problem about 70-80% of the time. The steering gets so "sticky" that it won't return to center. Then, I little later it will just free up. It doesn't seem to be one direction or the other or related to where I am in the steering travel. I figure it is either the pump or the box. The pump makes no noise. Can the balls in the steering box get worn and jam up then recirculate to free up? The only other thing I can think of is, the upper bearing in the steering column grinds and needs to be replaced. I have the part but it's been so freaking cold I haven't gotten to it. I guess it's possible for the bearing to cause the issue but it just seems like it wouldn't have the mechanical advantage to cause the issue.

I'm hoping it's the pump since that is the cheaper fix.

Thoughts are appreciated,

Jim