The internal workings of the gearbox have also changed over the years. Here we have as an example, the gearbox shaft. In the wake of efficiency measures the solid gearwheels of the first, the second and the reverse gear, or - in non coaxial gearboxes - also the driving wheel for the final drive - are milled directly into the shaft. The seating for another solid gearwheel is also provided for. Loose gearwheels often have needle-bearings, transmission drive shafts on ball rollers or diagonal rollers.