If you have a 2010 or 2011 Dodge Ram it's important for you to know whether or not you have a V-8 Hemi or a Turbo Diesel. This will determine which UJoints you'll need.
How Many Joints do You have, 2 or 3?
After you've determined which model your Ram is you'll need to know how many joints your truck has. You can do this by either crawling under your truck and counting how many you have or by calling Dodge and asking them yourselves. Either way it's important that you have this information because it will determine how many UJoints you'll need.
Inside or Outside Lock Ring?
The lock ring is important because it keeps the U-joint in place and keeps it from moving. If you have the wrong lock ring then the U-joint could rock back and forth and cause damage to the the yoke. If you have the outside lock ring it will have a circular shape with tangs and be at the top. If you have the inside lock ring then it'll look like a C and be at the bottom.