This is an optional CRC 64 Pitch, 72 Tooth, 16 Ball Pan Car Spur Gear. This spur gear uses 16 3/32" diff balls rather than 6 to 12 1/8" balls. This is done to reduce weight and maintenance by increasing the surface contact area, so less tension is needed on the diff nut to keep the diff from slipping.
NOTE: This is a 72 tooth gear! The mold on the first batch was made incorrectly and some gears may be labeled as 76T, but this is actually a 72 tooth gear and works perfectly other than being mislabeled. The mold is being corrected so that it will be labeled correctly with "72" instead of "76". Please be aware you may receive a gear that is mislabeled. CRC does NOT make a 76T gear and has no plans to add one to the line-up at this time. If it says CRC and 76, it is actually a 72!