Where'd this come from? Snap ring, rear axle

[beewstew]

While beating on the rusted left rear wheel, (alloy+rusted hub) of my 2004 xc70, this snap ring fell off some part of the passenger (left) rear axle/shock/gas filler tube etc. Guesses as to where it came from?

snap ring that fell off the left rear part of the car.

Edit: resolved, snap ring popped off the jack that was holding the car up!

Ring popped off the floor jack wheel axle while I was hitting the rim with a mallet.

[jonesg]

its something the tire picked up, if it was from the suspension it would have rusted away years ago.,,