HELP! My cordless drill just started making a weird grinding noise and stalls?!?

Hey all, need some quick advice. I was driving some 3in deck screws into pressure treated lumber with my 20v hammer drill (don't wanna name brands yet, but its the yellow one lol) and it started making this awful grinding/whining noise and then just stalled out. Battery is showing 2 bars. I let it cool off and tried again, same thing. It's not even that old, maybe 8 months?? Did I Fry the motor? Or is it the gearbox? I'm in the middle of a deck build and really dont wanna drop $$ on a new one rn. Any ideas?? Thanks!!

First off, 'the yellow one' tells me everything I need to know ;) But seriously, grinding + stall under load usually points to the gearbox, not the motor. If it were the motor you'd get a burning smell or it just wouldn't spin at all. Could be stripped planetary gears from too much torque. Are you using the clutch? If you're in Drill mode (not clutch) and bogging it down on 3in screws into PT, you're asking for trouble. What speed range are you in? Should be low gear (1) for that. Also check if the chuck is tight. Loose bit can sound like grinding under load.

Pete, I run a crew and see this all the time. 90% chance you cooked the gearbox or the motor brushes if its a brushed unit. That said, before you panic: does it make the noise with NO load? Spin it free, no bit. If it grinds free-spinning, gearbox is toast. If it only does it under load, could be the clutch slipping or a weak battery sagging under load. 2 bars on a 20v means nothing under load, voltage could be dropping to like 12v and causing the stall. Try a fully charged battery first. If that fixes it, it was just the battery. If not, its mechanical. Also, what brand battery? If its a knockoff Amazon special, thats your problem right there lol.

Before you do ANY of that, unplug the battery and let it sit for a bit. Grinding + stall can mean overheating, and if the motor is shorting internally you could have a thermal event. Not trying to scare you but I've seen guys melt tools because they kept pushing. Check for any burning smell or discoloration at the vents. If it smells burnt, stop using it, period. Also, are you wearing safety glasses? Because if that gearbox lets go under load it can throw pieces. And yeah, try a known-good battery first like Carl said, that's the cheapest diagnostic. But don't keep running it if it's grinding, you're just making it worse.

Follow up: Sarah's right about the smell test. Also, if you decide to open the gearbox (voids warranty probably) DON'T lose the shims. I rebuilt a similar drill last year and it was a $12 gear set on eBay. Took me 45 min. But honestly if its only 8 months old, just warranty it. Yellow brand has a 3 year warranty on most drills. Don't tell them you were driving 3in screws into PT in high gear lol. Just say it started grinding. They'll swap it. Save yourself the headache.