There was a similar post over on Cuda-Challenger.com
Someone posted that they are fairly easy to fix yourself. I didn't look into it any further because I sent my gauge cluster to GCAR to be redone. They are installing a quartz clock inplace of the origonal one.
The best thing to do is have the clock converted to a quartz movement. There is no difference in appearance or the way that the clock connects. You can call Shannon or Andy over at Redline Gauge Works (661) 259-8891 they do the conversion in a couple days for about $150 and it will have a 2 year warranty. Redline does the highest quality restorations on instrument panels out there with the best customer service!
I just finished repairing my clock today, got the parts and movement from RTE/Dash Worx took about an hour. Comes with detailed instructions/photos that are easy to follow. You can order on line