Summary: Some of the gears are fixed and or machined to the transmission shafts The other gears slide or spin on these shafts The gears that slide back and forth on the shafts have what are called Dogs These Dogs are knobs of metal that fit into holes in the gears beside them locking the two gears together The sliding gears are moved back and forth by Shifter Forks which in turn
Image Dimensions: 570 x 442
Image originally found here.