Regarding Matt Rathke's dead odometer on his '73 Bus:

I had a similar problem on the '82 Vanagon - both the regular and trip
odometers stopped working suddenly - no noises or other early warnings.
Speedometer was fine.

Looked like a small nylon gear failed.

Tried the local VW dealers for a replacement.  It is to laugh.

Tried a local speedometer rebuild shop - he had tons of the gears - he
said it is a chronic problem with VW/Audi odometers.

So, can I buy one?  Nope.  "It would be a violation of the federal
odometer-tampering laws for me to sell you one, you obvious criminal type,
but _I_ can rebuild your odometer for you."

So, he rebuilt it, for about $60 in 1988 dollars.  And it has worked
happily ever after.