A transmission for a vehicle, comprising: - an input shaft, a main shaft, and a countershaft, the main shaft being coaxial with the input shaft and the countershaft being parallel therewith, - first and second primary gear planes (P1, P2) arranged for torque transfer between the input shaft and the countershaft, - at least one secondary gear plane (S1, S2, Sr) arranged for torque transfer between the countershaft and the main shaft, - wherein the transmission further comprises a crawler shaft arranged in parallel with the main shaft, wherein the first primary gear plane comprises a first crawler shaft gearwheel arranged on the crawler shaft, and wherein the second primary gear plane comprises a second crawler shaft gearwheel arranged on the crawler shaft, - wherein the first primary gear plane comprises a first input gearwheel arranged coaxially with the input shaft, and a first countershaft gearwheel arranged on the countershaft, and the second primary gear plane comprises a second input gearwheel arranged coaxially with the input shaft, and a second countershaft gearwheel arranged on the countershaft, and wherein: - the first crawler shaft gearwheel and the first countershaft gearwheel are in meshing engagement with one another, and wherein the second crawler shaft gearwheel and the second countershaft gearwheel are in meshing engagement with one another, or - the first crawler shaft gearwheel and the first input gearwheel are in meshing engagement with one another, and wherein the second crawler shaft gearwheel and the second input gearwheel are in meshing engagement with one another, characterized in that: the second crawler shaft gearwheel being selectively rotationally connectable to the first crawler shaft gearwheel so as to engage a crawler gear of the transmission. - an input shaft, a main shaft, and a countershaft, the main shaft being coaxial with the input shaft and the countershaft being parallel therewith, - first and second primary gear planes (P1, P2) arranged for torque transfer between the input shaft and the countershaft, - at least one secondary gear plane (S1, S2, Sr) arranged for torque transfer between the countershaft and the main shaft, - wherein the transmission further comprises a crawler shaft arranged in parallel with the main shaft, wherein the first primary gear plane comprises a first crawler shaft gearwheel arranged on the crawler shaft, and wherein the second primary gear plane comprises a second crawler shaft gearwheel arranged on the crawler shaft, - wherein the first primary gear plane comprises a first input gearwheel arranged coaxially with the input shaft, and a first countershaft gearwheel arranged on the countershaft, and the second primary gear plane comprises a second input gearwheel arranged coaxially with the input shaft, and a second countershaft gearwheel arranged on the countershaft, - the first crawler shaft gearwheel and the first countershaft gearwheel are in meshing engagement with one another, and wherein the second crawler shaft gearwheel and the second countershaft gearwheel are in meshing engagement with one another, or - the first crawler shaft gearwheel and the first input gearwheel are in meshing engagement with one another, and wherein the second crawler shaft gearwheel and the second input gearwheel are in meshing engagement with one another,