3.73 Gears, mounting question

Can I just get the two parts of the gear and install it with my stock gear assembly? Or Do I have to buy the whole set for 500 bucks (rip-off)??

Thank you for your help.

I mean the pinion and the other thing ( I cant think of the name) You know they sell them in sets just the two gears.

you can certainly buy just the ring gear and the pinion. what you have to deterine, however, is which series carrier you have. if you have a 3.08 or lower stock rear gear ratio, then you have a series two carrier. if you have a 3.42 or higher stock rear gear ratio, then you have a series three carrier. basically, if the car is a v-6 its series two and if the car is an eight than it is series three. you will also have to buy an install kit in order to get all the seals, shims, nad bearings that you will need...