Automated mechanical transmission for a vehicle

An automated mechanical transmission for a vehicle, comprising:

• a main gearbox assembly comprising a main shaft and being adapted to be shiftable between at least one engaged state and a neutral state;
• a split gearbox assembly comprising an input shaft and being adapted to be shiftable between a first engaged state, a second engaged state and a neutral state;
• a countershaft;
• a crawler gearbox assembly comprising a crawler gear engagement member which is adapted to selectively engage and disengage a crawler gear defining a torque path from the input shaft to the main gearbox assembly via the countershaft, wherein the crawler gear of the crawler gearbox assembly is configured to provide a speed ratio of the input shaft with respect to the countershaft in the range of 1.5/1 to 5/1, wherein the crawler gearbox assembly comprises a first crawler gearwheel arranged on the input shaft and a second crawler gearwheel arranged on the countershaft and being in driving connection with the first crawler gearwheel, and wherein the crawler gear is engaged when the crawler gear engagement member rotationally connects the second crawler gearwheel to the countershaft;
• a gearbox brake;
• and
• a transmission control unit;
• wherein the transmission is configured to be settable in an AMT neutral state defined by the main gearbox assembly being in the neutral state, the split gearbox assembly being in one of the engaged states and the input shaft being in driving connection with a power unit causing the input shaft to rotate when the transmission is in use;
• wherein,
• when the transmission control unit obtains a request to engage the crawler gear from the AMT neutral state, the transmission control unit is configured to:
• apply the gearbox brake so that a rotational speed of the countershaft is reduced to a first predetermined rotational speed which is higher than a zero rotational speed;
• and
• when the first predetermined rotational speed is reached, release the gearbox brake, set the split gearbox assembly to the neutral state and engage the crawler gear by the crawler gear engagement member.