Which came first - chicken or egg...

[MikeTangas]

or, which part failed first?

On the 560SEL I just got (the one with the broken flex disk and tailshaft housing damage) I pulled the tunnel cover and drive shaft tonight. As soon as I opened the tunnel, I could see the carrier bearing was toast (rear flex disk is intact) but had no noticeable damage to the surrounding tunnel.

Which is the likelier theory:

The carrier bearing gave out, after plenty of whining, which put added stress on the front flex disk, causing it to fail.

or

The front flex disk was badly worn and causing "clunking", upon failing the carrier bearing was destroyed in the drive shaft melee within the tunnel.

My guess is option one, but I've been known to be wrong before.

I didn't get the tranny number while I was underneath today, will try to remember to next time I'm under there. The number will probably help with my next question. On the tailshaft housing, at approximately 5 o'clock (looking at the tailshaft) there is some type of sensor, attached with a 19mm hollow bolt. What is this sensor?

When I pulled the replacement tailshaft housing, I had the idea to get that sensor as well. Good thing, the one currently installed was hit, and the lead is still attached too, but it has been hit. What should I torque the hollow bolt to?

Thanks all.