18 volt 1/2" drive impact loss torque - Dewalt Tools & Hardware - Others

Well I was having the same problem and I found out that the p108 and p109 cut power when to much of the battery power is being used, kind of dumb just to say the new batteries last 4x longer( its because u can't use all the torque of the impact). Fortunately I've found out that the older batteries don't cut power such as the p104 p103 and the black ryobi batteries without the gauge indicator work the 1/2 " impact without cutting power

sounds like the variable speed portion of the switch is faulty, the only resolution is to replace the switch. Go to dewaltservicenet.com and with your model number you can download a parts breakdown and also order the parts needed. MAKE sure to write down the wiring of the switch before removing, it is polarity sensitive.

if it smells, like a burning then the motor is burnt and needs to be replaced.

same prob here, except its just one pack. mine is a 14.4 impact driver

Sounds like you have a gear broke that runs from the motor to the shaft. Take it apart and check it out. easy to put back together. atleast you will know for sure and may fix it while it's opened up.

Why do you think the brushes are worn.

i used a 1/2 18 volt impact wrench.i got it from snap on.it took the axle nut like it wont there.your axle nut torque is 232 ft lbs.that a lot of torque. you have to replace the axle nut and the circlip on axle shaft.

run all the way down before charging as far as possible then charge see if is any better

If this is a Dewalt tool as the picture indicates I would go to Dewaltservicenet.com and type in your model number for a manual, I also believe there is an area that you can click on for this information

all drill has brushes. this particular drill you need a motor assy
or switch. vibration & heat are common problem cu'z the drill not to properly