Need a Plumber

[zib]

Does anyone have any experience with Price Pfister faucets, specifically, Single handle lavatory? I've changed out a few in my day, but I've never seen anything like this one. Looking underneath the faucet, You have the water suppply lines and drain mech going through the middle hole..Everything together.

It's held on by, what looks like a giant C clip, or retaining ring.
Through the middle of the C clip is a 2 1/2 hex bar with a threaded rod inside it. I don't want to tear it up, so I thought I'd ask...I can't find anything on the net, maybe I didn't ask the right questions...

Rich