Motor works but no impact power - Hammering

Loss of power in an impact wrench can have many causes (worn/broken impact mechanism, worn motor parts, dirty motor, etc.). It will need to be disassembled and serviced.

I have never used that brand of impact, but I have used many others and I have never known an electric impact or drill to need oil. You need oil in an air powered impact because the air motor needs lubrication. The electric motors in electric impacts have sealed bearings and brushes that are meant to run dry. The actual impact assembly should be sealed as well, it should not need any oil.

Vanes in the air motor not sealing well

Impact wrenches rely on the force to the weights striking the anvil and this is obtained from their rotary speed which is obtained from the rate of airflow. Check for restrictions all along the line from your air supply, the nose, the fittings and also the trigger mechanism. Also check the exhaust for obstruction and that the ports in the motor nave not become misaligned. The motor should run at about 8000 RPM.

i have the same impact an replaced trigger switch. i think it was 38,00, had the same thing happen with my de walt xp hammer drill.U can check switch continuity before replacing

sounds like a winding in the motor has a short in it

It soulds like either the striker is stuck or the ram. Unless you are mechanically inclined I would recommend taking to a repair shop. If you are give me the exact model number and I will see if they make a repair kit and get you a schematic for this tool before you start dissassembly.

If the motor is working good then the problem is with your hammer and anvil. One side is probably worn more than the other. This occurs when the impact is being used more in one direction. If the motor is what is hanging up, you have an end plate problem and they need to be honed or replaced and the rotor needs inspection.
There may also be restricted flow of air that is causing your problem. Check to make sure air flow is good inside tool. Ports should not be jammed with any debris. Sometimes scale from inside pipes builds up and can cause problems if impact is used on an unfiltered line.

make sure the selector switch is in full rev or full forward and not in mid throw goose the trigger and turn the selector at the same time

An impact wrench works in the manner suggested by the name of the tool: through the principle of impact. In order to understand how an electrical or air-powered impact wrench works, it helps to know first how a manually powered impact wrench operates. A manually powered impact wrench looks like a fat screwdriver; on the end where the screwdriver blade normally goes, you can snap on screwdriver bits or sockets.