Ok so I already did a bunch of searching but was wondering if I could get some extra help. Since I got my car it had no function from the speedo. I figured it was a bad cable. I pulled the driven gear/cable out of the tailshaft to try and spin it and see if speedo would move and it did. I found that the drive gear was completely free spinning on the shaft and the clip fell out.

So if I pull off the tailshaft housing, I can remove the gear from the shaft? How exactly would that work? I'm thinking I'd want a new gear while I'm at it because I dont know if its possible that the gear is too loose.

 

Changing speedo gears (4L60/700-R4)
I did it cause I went from 2.73s to 3.42s, easy as pie dude!
Here is a tech article on it.

 

Yea I found that with some searches. Pretty helpful. I'm trying to make sure I get the parts beforehand. My gear looks fine but I dont know why it came off in the firstplace other than when the tranny was swapped or rebuilt. I dont know how they could put it back on wrong. I want to grab a new clip and seals just in case while I'm in there.