A few weeks ago, I gave up on trying to make the mechanical part of the drivetrain out of Lego for my tank.
I also found that the drill isn’t strong enough to power both tracks, and that the battery life isn’t very good for constant use. So, I’m going to use some Power Wheels motors because they’re fast, strong, and small. So, after a few hours of looking online for what I need to make them work, I just need to order them. The only electronic part I’m not very sure about is the speed controller, as it doesn’t say if it is for brushed or brushless motors. I’m also going to have to find a way to connect the motors to the axle for the tracks, as the motors have a large adapter that connects to the wheels of a Power Wheels car.
Stuff That Jack Built 