Grizzly Locker For GM 10.5 14T Differential 40 Spline 4.10-Down Ratio 14T 10.5 Inch GM 4.10&Dwn 40 Spline Grizzly Locker Carrier Assembly (40 Spline Case W/ Locker) Yukon Gear & AxleThe Yukon Grizzly Locker is a mechanical automatic locking diff thats engineered for rock crawling, serious trail running, off road racing, and drag racing. Its patented design features innovations that make it tougher than other lockers. Everything about the Yukon Grizzly Locker is hardcore, its casing and gears, its advanced gear tooth design, and its impact on traction and performance. The Yukon Grizzly Locker is a mechanical positive locking