Speedometer not working.

[GMCJOE]

No, it's very easy. Unscrew the cable, take the retainer off, make sure you mark the speedo housing so you have the right position when you install it back, then you can pull it right out of the housing. Sometimes the gear stay in when you pull it out, sometimes it stays in the the transmission. Put the new on in, and everything back together. Replacing the speedo gear is very easy. I would suggest taking the cable off and hooking it up to a drill and seeing if the speedometer actually works before doing the gear. I know you said the gauge and cable is good, but you didn't say how you tested it.