Is my Milwaukee drill defective?
What size battery do you have? When using large bits the drill draws a high amperage the smaller batteries just cannot sustain a heavy load. For example a 1 amp hour drill may be able to drill an inch but jump to a 4 amp hour or larger and it may not over heat and shutdown at all, I found this especially true with my battery band saw, trying to cut 2" pipe my small batteries just could not keep up but the big ones made cut after cut with no problems.