The massive 10.5-inch Tundra rear ring gear, comparable to a 14-bolt or Dana 70. The big axles were offered with both 4.10 and 4.30 ring-and-pinions. Since most are found with the tow package, the majority will be 4.30:1. The smaller 9.5-inch diff is available with 4.10 and 3.90 gears, again the lower with the tow package. We like that this low-pinion axle is not extremely low like a 14-bolt or a Ford 9-inch. This results in a higher rear driveshaft, less heat created by the gear engagement, but slightly less pinion-to-ring-gear-teeth engagement due to less hypoid drop.