Clicking sound from right rear

[Siggy]

I hope I can accurately describe this. I'm having an issue that I can't seem to track down.

2006 3.0i and I get this "clicking" from the right rear that comes and goes. I say clicking but it's not really a click. It almost sounds like some is taking a paper cup and tapping the bottom of the cup with a pencil. It's a "pop pop pop". Almost like the problem you used to hear it classic cars when the speedometer cable was dry. Like something that is bound up and then lets go causing a pop. It's not super loud and it goes away under 20 mph or so. It does change cadence but it doesn't always appear to follow the speed of the car but I could be wrong about that detail.

It comes and goes from time to time.

What I've done is pull the rear wheel off and look for anything obvious. I can't see any signs of anything rubbing. I pulled the rear brakes off, cleaned and lubed everything and put them back together and adjusted the right rear. It was so loose it wasn't hitting so I thought I had found the issue. I put it all back, test drove it. Dead quiet. Then, the next day, it was back. When it's doing it, if you pull up the parking brake slightly, the noise doesn't stop.

If you go around a curve, for the most part, it goes away when there's a load to the side. If you put the regular brakes on lightly, it doesn't stop.

I've pulled most everything I can see apart, aside from the axle itself.

Anyone got any idea at all?