A while back my odometer stopped working as well. I ordered replacement gears from odometergears.com, installed them and it worked OK for a while.
Then it seemed it would work sometimes, then not work anymore. I inspected and lubed the gears a couple of times with no real change. Recently the odometer stopped working all togather. I found this thread and embarked on fixing mine as well.
The gears I installed were working just fine as I can sping them and the odometer moves fine, which makes me believe I have an electrical problem:
Using some solder wick and a good iron, I unsoldered the five points that hold the speedometer to the unit:
I found this:
Unlike the OP, my 85 300SD only has two capacitors. One I can clearly see as 220/6, the other one I can't make out for sure, but I beleive it is 1.7/16. Does this seem right. I know very little about these. I plan on picking some up at radio shack over lunch and putting this back togather.
Any good eyes here that can make out the numbers on the smaller cap?
Thank you in advance!