A differential pinion shaft nut holds together components on the shaft. The shaft nut is one of the components that transfers power to your vehicle's wheels. If it loosens and falls off, it can cause other parts on the differential pinion shaft to fall off or loosen. Signs you've lost your differential shaft nut are a locked transmission or strange noise coming from your axle. At O'Reilly Auto Parts, we have a selection of replacement differential pinion shaft nuts for most vehicles. Check out our inventory and find the right differential pinion shaft nut for your vehicle.