Yukon Grizzly Locker for Ford 9" with 31 spline axles, racing design. The Yukon Grizzly Locker is the ultimate in locking differentials for street, off-road, & drag racing. Grizzly Lockers provide 100% power to both tires, while still allowing for disengagement while negotiating turns. This unit requires the use of a 3.250" dropout. Use carrier bearing/race numbers LM104949/LM104911. The Yukon Grizzly locker uses 8620 internals and a patented design to provide maximum strength and reduce common failures. Assembled in the USA! This unit has been approved for competition in NASCAR National & Touring series. This is a race unit designed for extreme off road use or racing. All Grizzly Lockers are backed by the best warranty in the business! Yukon covers the replacement unit and covers any collaterally damaged parts and associated labor, up to $2,000!