I had a Makita DHP456 brought to the guy said it was smoking after drilling 6 holes, i changed the motor and brushes and tested the electrics and sent it back working perfectly, he returned it a few days later saying it was still smoking.
so i looked at it again doing 100% test no problem wasnt smoking driull 14 holes not even warm.
now we get to the muppet part when cutting holes in a ceiling make sure you use a sharp cutter also do not hold the drill body at the rear of the motor because it cuts the air flow off also the heat sink is on the right side so yr hand and fingers cover the vents, simply use the machine correctly hold the handle pull trigger and let the cutter make the hole do not force it with other hand over vents and it wont smoke