Ideas on what's causing my click/tick/rattle noise?

halfafish said
I assume you are talking about the kind with a hollow tube that feeds the gauge inside the cab? If so is that better than an electric one? I have a set of Auto-Meter gauges in my cart at Amazon but they are all electrically powered.

I don't think so, it's the one that was on the truck. I took it apart and spec'ed it before reassembling - it was in good shape and did not need any rebuilding. I'll see if it's the HD version but I doubt it.

I don't think there is an oil passage problem anywhere. I ran wires through them all then flushed them during engine bath time to make sure all were flowing.

Some electronic oil pressure gauges are dampened so they do not respond immediately. That is why I like mechanical oil pressure gauges. What the mechanical gauge shows is what is happening.
Most mechanical gauges will come with a nylon pressure tube. Those will last a long time, but if you want something more robust both copper and steel tubes are available. With hard pressure tubes make a loop at the end that connects to the engine to allow for movement and vibration.