3. This is an excellent example why you should take a close look at the driveshaft and U-joints after every race. Dirt Modified racing is hard on the stock-style U-joints because the pinion angle can swing so severely as the suspension moves. Once the joint starts to wear you can get marks on the joint like you see here. Strickler recommends disassembling and cleaning the U-joints after every race. And if you see wear like this, it’s time to replace the unit.