Power steering question

Hello
My truck does not always do this, but when I start the truck up and I am pulling out or backing out of a parking spot. It feels like I have no power steering and I have to force the wheel over. You can hear the pump growling a little.

After that the steering is fine. I can stop at a light and steer just fine. I installed a new belt, idler and tension pulley last weekend so that shouldn't be an issue. Would draining and filling the reservoir with new fluid help? Or am I looking at a possible issue with the rack or pump failure?

Any ideas would be apricated.

 

I doubt the fluid change would help. These trucks do have a known issue with the racks. I think the rack issue is around 2012 years..