Grizzly Locker Ford Sterling 10.25" or 10.5", 35 Spline P/N YGLF10.25-35. The Yukon Ford Sterling Grizzly Locker is a mechanical locking differential and is often compared to the Detroit Locker. It features 8620 internals for maximum strength. It's patent pending design reduces common locker failures. All units assembled in the USA!