I bought a used air impact wrench which worked, but felt like something was wrong and it was making a strange noise. A good oiling through the oil port would have likely fixed the problem. But I decided to take it apart. So in this video I disassemble a Sears Craftsman Air Impact Wrench model 875-188840, clean, lube and re-assemble it. So if you want to know what’s inside an impact wrench. It did fix the problem.