What is the difference between Ring and Pinion gears, and Reverse Ring and Pinion Gears.

 

Reverse cut gears are for the front differential. If you put the gears from the rear end into the front, (if they would even fit, I don't know) in 4wd the front tires would spin the opposite direction of the rears. If your truck isn't 4x4, just ignore anything that says reverse cut.