SHACMAN X3000 FAST 12JSDX240 Gearbox Assembly Heavy Duty Truck Manual Transmission System Spare Parts

The FAST 12JSDX240 Gearbox Assembly is a 12-speed manual transmission designed for heavy-duty truck powertrain applications and belongs to the manual transmission system. With a rated input torque of 2400 N·m, the gearbox is designed to transfer engine power to the driveline while providing multiple gear ratios for different operating conditions. Its 12 forward speeds allow the truck to maintain a suitable engine operating range during starting, heavy-load acceleration, climbing, highway driving, and changing road conditions, while the two reverse ratios provide additional flexibility during low-speed maneuvering. The standard 12JSDX240 configuration has an installation length of approximately 983.5 mm, a maximum input speed of 2600 rpm, and a reference oil capacity of approximately 16.5 L. During actual vehicle operation, transmission performance depends on correct clutch adjustment, suitable lubricant, proper shift operation, and the condition of internal gears, shafts, bearings, and synchronizers. Difficult gear selection, gear jumping, abnormal transmission noise, vibration, oil leakage, or changes in shifting behavior can indicate that the gearbox requires inspection. When replacing the complete 12JSDX240 transmission assembly, buyers should verify the transmission model, input/output interface, clutch housing, PTO configuration, shift mechanism, mounting dimensions, and vehicle application before purchase. This is particularly important because FAST offers several visually similar 12-speed transmission models, including 12JSDX240A, 12JSDX240T, 12JSDX240TA, and 12JSDX240K/260K, but their specifications and configurations are not identical.