90q odometer gear broken but not the usual one

[E. Roy Wendell IV]

I just disassembled the odometer on my new to me 90q. I already had a  
new 15 tooth gear in hand thinking that it had disintegrated just  
like the one in the odometer of my 200. Not necessarily so. The 15  
tooth gear was intact although it seemed like it was stuck in the  
ring gear and did want to move. Then I noticed chunks of a blue-green  
plastic/rubber substance on the back side of the carrier for the 15  
tooth gear. Turns out it's the remains of the gear on the side of the  
carrier than drives the spindles on both odometers. Oh great, yet  
another mode of failure.

Here's a good picture of what the new part looks like http:// 
www.paspeedo.com/vdo_16Tooth_2.htm

As an aside, both this gear and the tiny 15 tooth one that normally  
fails are made of a very soft, almost rubbery plastic. I'm guessing  
that the point was to keep down gear noise but as a consequence the  
material doesn't seem to be stable over the long run.

The guys at http://www.carradio.com/speedometer_gears.html don't show  
this carrier on their website so I guess it's time to talk to PA Speedo.

Any body have a bead on how common this failure is? Monkey lads  
trying to extract the cluster previous to my ownership have bused off  
the two mounting ears above the column so I'm thinking I might just  
as well get another used cluster. Anybody got one laying around that  
didn't survive some other repair?

Roy