⚙️ Transmission (Gearbox)
The gear case that takes drive from the spur gear and passes it on to the differential or driveshafts.
Most electric RC cars are single-speed, though some large-scale and crawler transmissions offer two. Its internal ratio is part of the final drive ratio, so it matters when comparing gearing between different models.
What it actually does
The transmission is the gearbox that takes drive from the motor and sends it to the diffs. It contains the spur gear, often the slipper clutch, and on 4WD models the centre diff or the output to front and rear. It is where most of the drivetrain wear happens.
In practice
Designs range from a single-speed with a straight-through gear train to two-speed boxes that shift under load, common on larger nitro models. Access matters more than it sounds — a transmission you can open without stripping the whole car is one you will actually maintain.
Worth knowing
Listen to it. A change in gearbox noise is usually the earliest warning of a chipped tooth or a failing bearing, well before anything fails outright.