I have a Sony DC2 with 28### with no cracked center gear or signs of stress, is it possible that their was a batch that didn't have problems with the center gear, or you think it may have been replaced at one point, looks like walkman was never taken apart besides the finger prints on the plate to the capstan

I'm guessing it's a lucky unit that has either not seen much use or was kept in stable temperatures, preventing the metal ring from expanding. Batches of plastic are known to vary as well. Great find.

My experience shows:
There are about 5% of the gears have survived.
DD33 is not counted.
I think it is the factory tolerances.

I have DD, DD2,  D3 and  a DD100 with original unbroken gear.
And I have 3 unbroken original Sony replacement part NOS .

Have found that usually only the DD33 has a good chance of today still having an intact center original gear.  All other DD units would agree with Renzgi very very small % survive with original intact gearing. 

   I have a DC2 out of UK that has orig. gear and a DD33 but all my others are cracked or repaired.   Know for fact my DC2 has orig. as got it from orig. owner who was owner of a stereo music and equipment family owned store was fathers.  When purchased the repair tech sony trained who did repairs on walkman in 80's and 90's went over my DC2 to check it out and clean/lube.  All was good inside.  Believe that a player that has not seen much temp. variances  best to survive.  Mine was kept almost exclusively inside the home where temp. probably only varied 10-15 degrees. 

   Have to watch if buy one that is shipped AIRMAIL as the very cold temp. in baggage area probably can contribute the center gear to crack if not already or make noticeably worse.  Having one shipped in winter where box goes in and out of warm/cold temps several times before reaching buyer probably also increases chance of cracking or making it much worse.  Seems best is shipping during reasonably warmer season.

Retrodos

Is your center gear still intact?  I bought a DC2 with the center gear still intact, but worried it's just a matter of time.

Philip

Meanwhile I have another two gears that are broken. One in D3 and a NOS spare parts.
But worry me much more makes this part here. Of these break more and more over the years.

...I had three mint - all broken by now - even that stored cool and dark :-(

Funny my DD-100 and one of my DC-2 don't click, never even opened...

A center gear made of plastic that will not crack sounds like fiction.  I mine breaks I'll make an appointment with good dottor.