I was having problems with my speedometer on my 1981 Seville V-6 and thought it was in the dash box unit. Lo and behold, my mechanic called yesterday morning and said that the drive gear had been broken. So, I spent the morning trying to find replacements. Every one seemed to be delighted to tell me that the gears were no longer available.
After lunch, I went down and picked the old parts up and found that they are molded in color. Mine is a twenty nine tooth in green. I was able to match one up from TCI in Mississippi. It even matches the # in my Master Parts Book. The larger driven gear is also green but is no longer available, so I very carefully trimmed any burrs from the gears and smoothed them with a nail file. So, hopefully this part will still hold up.
The # on this transmission is THM 325. Last weekend I used the speedometer on my Garmin when I went to the Fall Festival. Luckily the car did not have to move to pick up a first in Primary.