Gear train noise

[Magard]

I been having a slight noise in front end of engine. Almost sounds like a belt maybe but I’m thinking it might oil pump. It’s coming from the bottom of engine somewhere around the balancer.
Seems a little worse when compressor is engaged hard to tell. I been reading on past posts about oil pump not being shimmed properly. Could a pump gear rattle a little even if it’s under pressure pumping oil? Also when you open the fill tube when running you can’t hear anything unusual coming from the fill tube. It’s a 2250 that I just In framed about 30k miles ago. I guess I’m pulling the pan tomorrow.