The RTD11509C is a 9-speed manual transmission assembly manufactured by Fast Gear (法士特), widely used as a driveline component in XCMG QY70K and QY50K truck cranes .
1. Installation Location
This gearbox is installed in the driveline between the engine and the drive axles, mounted on the chassis frame of the crane carrier. For XCMG QY70K and QY50K cranes, the engine is typically a Weichai WD615.46 or similar model, and the gearbox is coupled directly to the engine flywheel housing . Installation requires proper alignment and securing with mounting bolts, as well as connection to the clutch, driveline shafts, and shift linkage.
2. Function
The RTD11509C provides 9 forward gears and 1 reverse gear, with a maximum input torque rating of 1490 N·m . It is a manual transmission with a dual-countershaft design and is non-synchronized in the main section, with a weight of approximately 270 kg and oil capacity of 12.5 litres . The "R" in the model designation indicates a range-type design, while "T" denotes twin-countershaft construction . The transmission enables the crane to achieve road speeds up to approximately 80 km/h and provides the necessary torque multiplication for heavy-load lifting operations .
3. Maintenance and Service
Regular maintenance includes checking and maintaining the transmission oil level (12.5 L capacity) with the specified grade of lubricant . The shift mechanism uses dual-H control, which can be configured for single- or dual-lever operation . If shifting becomes difficult or noisy, inspect the clutch adjustment and shift linkage before assuming internal gear damage. When replacing this gearbox assembly, ensure the new unit is properly aligned with the engine and driveline, and use new seals and gaskets to prevent oil leaks. The gearbox itself contains no user-serviceable internal parts; internal repairs should be performed by qualified transmission specialists.
4. Important Notes
Always verify the gearbox part number (RTD11509C) matches the original specification for the specific crane model (QY70K or QY50K). Ensure the transmission is compatible with the engine output and driveline configuration. After installation, check all shift operations through the full gear range before returning the crane to service.
