Volvo c303 c304 Upgrade Portal Gear

- Reinforced 8620 forged steel 

- Ratio: 13x27 (2.0769), 0.7% different with original 16x33 (2.0625); 
First time buyer we strongly suggest to change all four c303 / six c304 portal gear to get desire upgrade result.

- Designed in a higher gear modulus so gear can get coarser, mean stronger teeth.