The Custom Gearbox is a cable corner added by GregTech 6. It is used to change the direction, split, or augment rotational power RU.
A Custom Gearbox starts with empty faces when placed, and must be configured in order to transmit power.
Gears can be added to any of the six faces of the Custom Gearbox by using a Wrench on the face while the correct type of gear is also on the player's hotbar. Using the Wrench on a side that already has a gear will take off the gear, dropping it in world.
The internal axle can be re-aligned by right-clicking with a Monkey Wrench on the new axis, or disengaged by right-clicking on the axis that already has the axle.
RU power entering a face with a gear on will transmit that power across block edges to any adjacent face that also has a gear on it, while reversing the direction. Once RU power reaches a face with the axle, it will be transmitted to the opposite face, keeping the same direction. The direction and speed of rotation of each face is set once per tick, it will only accept additional torque if both match.
Just like real gears, there are many possible sets of gears and an axle that will lock rather than rotate. The Magnifying Glass reports whether the Custom Gearbox can turn.
If the Gearbox receives power while in a locked state, or if RU is received at a speed greater than the gearbox material can handle, the input gear will shatter into Scrap.