If your odometer has stopped or is slipping, get a new VDO gear from Palo
Alto Speedometer.  It is not worth horsing around trying to fix the old
one.  BTDT. They sell them for $18 each with a $20 minimum order.  (I
ordered three.)  I fixed my '89 Jetta's odometer over the weekend and I
plan on looking at my friend's '87 Vanagon in the future, with one left in
reserve for my '85 Westy!    I literally had to tap it on with a hammer and
punch.   Maybe one of the vendors on the list would like to stock this
item?  I am sure you could get them for way less and sell a bunch of them.
It is a common part for many of the VDO speedos.  They knew exactly what
gear I was talking about--like they had fixed thousands of them before--but
would  not give me an actual VDO part number.
See:  http://www.paspeedo.com/
                                                             Jay