A gearbox for a vehicle, the gearbox comprising: a split gearbox, a main gearbox and a range gearbox, which is shiftable into a low range gear position and a high range gear position; the range gearbox comprises: a planetary gear with a ring gear wheel, a sun gear wheel and a planet carrier, on which at least one planet gear wheel is rotatable mounted, which ring gear wheel and sun gear wheel engage with the at least one planet gear wheel; a gearbox housing surrounding the planetary gear; a first axially movable coupling sleeve arranged to engage the planet carrier with the gearbox housing; and a second axially movable coupling sleeve arranged to engage the ring gear wheel with an output shaft for achieving a reverse gear in the gearbox, wherein a crawler gear in the main gearbox is arranged to transfer torque through the gearbox when the range gearbox is shifted into the reverse gear so as to make the vehicle drive in a reverse direction, characterized in that the width (wC) of a crawler gear wheel (211A, 211B) of the crawler gear is smaller than the width of a gear wheel (204A, 204B) in a gear in the main gear-box having the second largest gear ratio. a split gearbox, a main gearbox and a range gearbox, which is shiftable into a low range gear position and a high range gear position; the range gearbox comprises: a planetary gear with a ring gear wheel, a sun gear wheel and a planet carrier, on which at least one planet gear wheel is rotatable mounted, which ring gear wheel and sun gear wheel engage with the at least one planet gear wheel; a gearbox housing surrounding the planetary gear; a first axially movable coupling sleeve arranged to engage the planet carrier with the gearbox housing; and a second axially movable coupling sleeve arranged to engage the ring gear wheel with an output shaft for achieving a reverse gear in the gearbox, wherein a crawler gear in the main gearbox is arranged to transfer torque through the gearbox when the range gearbox is shifted into the reverse gear so as to make the vehicle drive in a reverse direction, characterized in that the width (wC) of a crawler gear wheel (211A, 211B) of the crawler gear is smaller than the width of a gear wheel (204A, 204B) in a gear in the main gear-box having the second largest gear ratio. a planetary gear with a ring gear wheel, a sun gear wheel and a planet carrier, on which at least one planet gear wheel is rotatable mounted, which ring gear wheel and sun gear wheel engage with the at least one planet gear wheel; a gearbox housing surrounding the planetary gear; a first axially movable coupling sleeve arranged to engage the planet carrier with the gearbox housing; and a second axially movable coupling sleeve arranged to engage the ring gear wheel with an output shaft for achieving a reverse gear in the gearbox, wherein a crawler gear in the main gearbox is arranged to transfer torque through the gearbox when the range gearbox is shifted into the reverse gear so as to make the vehicle drive in a reverse direction, characterized in that the width (wC) of a crawler gear wheel (211A, 211B) of the crawler gear is smaller than the width of a gear wheel (204A, 204B) in a gear in the main gear-box having the second largest gear ratio.