I like motorized LEGO very much, but one thing I don't like is grinding gears, which occur when a drivetrain isn't constructed solid enough. The torque of the motor causes the gears to come apart, creating an awful clicking noise and reducing driving power. This mostly happens in a transversive gearing, since they have only a small surface to transfer the power. LEGO® has make an excellent part for this: the knob-wheel.
This part is compattible with no other LEGO® gear, only with itself, but provides a very nice transversive gearing.
I've created a drivetrain with this part, which includes a differential. It will be used in my next MOC, which is supposed to go quite fast. The design has 3 internal gearing options (as you can see in the video). If your model isn't too big, you could also use the combination of the 8-tooth and the 24-tooth:
But the 8-tooth gear isn't very strong. I've already damaged some when testing models which had flaws. These parts are normally omitted in drivetrains with much torque in my models.