Accessories:Big Helical gears-1pcsSmall Helical gears-1pcsOriginal Name / Part No:8978Part location:Inside front differential caseDoes this product replace a specific part or function?yesProduct major function & usage:Improve the transmission of power in the differential caseMajor advantages of upgrading to this product:1. Precision machined helical spiral cut gears offer inherently greater strength and smooth operation than the factory bevel cut gears2. High carbon steel construction3. Stronger than the stock bevel Plastic gears4. Maintains the stock 37T/13T ratio