i know i have to get a new speedometer gear (the new gear is a 21 tooth i believe). Here is the stupid question, what does this new gear replace, a gear in the transmission or does this gear go somewhere else??
Yep, its in the transmission. Its up toward the rear of the transmission on the right side if i remember correctly. Just follow the speedo cable under the car and it'll lead you to the right place. From there you have to remove a bolt to get the cable off the transmission, and after that all you need to do is remove a small metal clip from the end of the gear to get it off.