What are the types of gearboxs used on hgvs?

Specifics for European trucks, I'm not sure about, but universally, the manual shift transmissions will be unsynchronised, consisting of anywhere from 8 to 18 gears total, although synchronised gearboxes with just five, six, or seven gears are often seen on single axle straight trucks/rigids. There are also automatic transmissions available, as well.