DIAGNOSIS A whine or grind in high gear (setting 2) points to worn or dry planetary gears in the gearbox, not the motor.
FIX The gearbox needs lubrication. You must disassemble the drill to access the gear assembly. Clean out any old, gritty grease and apply a moderate amount of high-quality lithium grease (not heavy grease) to the planetary gears and sun gear.
IF THAT DIDN'T WORK If the noise persists after lubrication, the nylon gear carrier or the metal planetary gears themselves may be worn or chipped. You'll need to source a replacement gear set specific to the CMCD700 model.
HEADS UP Running it with dry or damaged gears will cause rapid failure. The whine is a warning. Continuing to use it will strip the gears entirely, leaving you with a drill that only makes noise.