Transmission cutaway
1 - input shaft; 2 - driven bevel gear of the differential mechanism; 3 - drive shaft; 4 - conical wheel of the differential mechanism; 5 - main shaft.
Engine power is transmitted through the clutch to the transmission input shaft. There are 6 gears attached to this input shaft (including reverse), which are in constant mesh with 6 gears on the drive shaft. These gears can rotate freely until one of them, when a certain gear is engaged, engages with the corresponding gear on the drive shaft. The ratio of the number of teeth of a particular pair of mated gears results in the corresponding gear ratio.
Renault 19 has fully synchronized forward gears. The gears on the drive and output shafts are supported by rod-like rollers («needles»). Thus, there is no permanent attachment between the shaft and the gears. The gears always mesh with each other. When shifting gears, meshing occurs between the gear and the shaft, and not between the gears. To equalize the rotational speed of the shaft and gears with each other, part of one shaft slides on the surface of the other shaft by means of rubbing elements. Due to friction, the faster shaft is slowed down until, at equal (synchronous) rotational speed, it will not be possible to produce thrust-transmitting engagement.