1971 GMC Pick-up Truck Differential Carrier K35/K3500 Pickup - Dana 60 - Yukon Grizzly Locker - Aftermarket 40 Spline Upgrade - 4.10 and Down or Thick Gear Ratio's - Front guaranteed to replace your current 1971 GMC Pick-up Truck Differential Carrier K35/K3500 Pickup - Dana 60 - Yukon Grizzly Locker - Aftermarket 40 Spline Upgrade - 4.10 and Down or Thick Gear Ratio's - Front. 1971 GMC Pick-up Truck Differential Carrier comes new OEM 1971 GMC Pick-up Truck Differential Carrier aftermarket new 1971 GMC Pick-up Truck Differential Carrier of remanufactured 1971 GMC Pick-up Truck Differential Carrier K35/K3500 Pickup - Dana 60 - Yukon Grizzly Locker - Aftermarket 40 Spline Upgrade - 4.10 and Down or Thick Gear Ratio's - Front.