Speedo drive gear on a T18/19?

[Diesel JD]

How does it all work together? What coler drive gear do I need? The yellow or the green? It shouldn't cause any problems reading with an automatic dash right? Thanks. If it matters I have 3.55 gears and this is a T18.

 

[NCheek]

Basically the gear rides on the tailshaft and has a steel ball that keeps the gear from rotating on the shaft. Just swapped mine a few months ago, and the gear is interchangeable between t-18 and t-19. Ford no longer carries the 7 tooth yellow drive gear, but they have others that will work just fine, but will need a different driven gear combo.

 

[Diesel JD]

I have a few of these gears laying around(yellow ones) what if the ball is missing or loose? Any way to fix it? How about on the speedo cable are there different color codes for different gear ratios just like with the C6? Or all the same? My mechanic friend had a death in the extended family so he's understandably taking a couple days off, and then there's the 4th,but I'd like to get these other little issues I can take care of myself hammered out in the interim so hopefully by early next week I can be rolling.