i believe they are yukon. this is the part number on the ring gear.( k t8-529 7x37 09 01 a2x ) i don't really now the miles but no signs of rough use. i would have used these if i knew that it was in my front axle when i bought it. i would have bought a locker for the front but, i have new gears in my truck and and have an extra 529 3rd.