does the warranty on my milwaukee m18 drill cover the chuck if it gets loose?

It depends on the cause. A defect in material or workmanship is covered. Damage from misuse or an accident is not.

FIX:

1. Stop using the tool.
2. The chuck is a part of the tool, so it falls under the five-year limited warranty.
3. Return the tool, freight prepaid and insured, to a Milwaukee Service Center for examination.

IF THAT DIDN'T WORK: If Milwaukee determines the looseness is from normal wear and tear, it is not covered. The warranty excludes failures from normal use exhausting the life of a part.

HEADS UP: Include a copy of your proof of purchase. Do not attempt to repair or tighten the chuck yourself, as unauthorized repairs void the warranty.