I tear things apart so you don't have to. Well, not really – I tear things apart because I am curious about what's inside, especially when the manufacturer makes a big deal out of it. Lately, the big deal has been brushless motors so I disassembled DeWalt's new brushless impact driver and shot these photos.
I didn't mess with the gears or battery because they're no different than what you would find in a tool with a brushed motor. And I didn't ask DeWalt how to take the tool apart so don't take my instructions as gospel. The impact driver worked fine after I put it back together – but taking it apart probably voided the warranty.