I've got a Dewalt 14.4V cordless drill on long-term loan from a friend (so I *have* to fix/replace). It's slipping, and the amount of torque needed to make it slip is going down, quite rapidly. I partially disassembled it to find a fairly self contained motor unit, a chuck that appears to be attached with a reverse-handed screw down the spindle (though removing it didn't suddenly make the chuck fall off, I imagine it's a pretty tight fit), and a gear control spinner.
It is not the chuck that's slipping - I can hold the whole body of the chuck still.
Is this a common problem, and is the solution easy/hard/buy a new one?