What are the shifting techniques for FAW Jiefang 12-speed transmission?
4 Answers
FAW Jiefang 12-speed shifting techniques: 1. When the engine reaches the appropriate speed and RPM for shifting, the gear engages smoothly. Since this type of transmission doesn't have a synchronizer, clutch operation isn't necessary for gear changes after starting. 2. If the vehicle speed and gear position don't match or if the throttle input is incorrect, the gear won't engage even with clutch operation, resulting only in gear grinding noise. 3. Shifting shouldn't be done by sound but rather by monitoring engine RPM. Start in first gear, shift to second when reaching about 10 km/h, shift to third around 20 km/h, and use fourth gear for speeds above 30 km/h.
I've been driving FAW Jiefang trucks for many years, and shifting the 12-speed gearbox really requires a good feel. When driving, I first familiarize myself with switching between the high and low gear ranges. Generally, I shift into the high range at speeds of 20-30 km/h to avoid sudden acceleration on slopes. Before shifting, I pay attention to the tachometer and shift when the RPM is between 2000-2500 to reduce gear grinding and wear. When starting, don’t stomp on the clutch pedal—engage it lightly and quickly to avoid prolonged half-clutch conditions, which can easily burn out the synchronizer. Be extra careful when hauling heavy loads; shift steadily to prevent stalling or rolling back on slopes. Gaining experience through more driving is key. I also struggled with jerky shifts at first, but after daily long-haul trips, it became smoother. Remember the feel of the truck—don’t just rely on the gauges. Listen to changes in the engine sound, and your shifting will become more fluid and natural.
When I first learned to drive the 12-speed transmission of the Jiefang truck, I was all thumbs, often shifting into the wrong gear or experiencing slippage. My mentor taught me to start with the basics: distinguish between high and low ranges when starting—use the low range for climbing hills or low-speed driving, and the high range for cruising to save fuel. Don’t rush when shifting; complete the clutch operation within two seconds and match the vehicle speed. For example, shift to 2nd gear at 10-20 km/h to avoid lugging the engine. Don’t get discouraged by mistakes. Practice starting with an unloaded truck to get familiar with the clutch feel, and avoid excessive gear changes, as beginners tend to overdo it. Trucks are designed for heavy-duty transport, so downshift before slowing down when loaded to protect the transmission. Now, I drive smoothly mainly by repeating operations to build muscle memory and reduce errors. Safety first—moving the gear lever slowly at lower speeds is always the right move.
Operating a 12-speed transmission requires understanding some basic principles. Separate the high and low ranges when shifting, ensure RPM synchronization during gear changes to avoid impact caused by large RPM differences. During normal driving, I keep it within a reasonable range, such as using light throttle acceleration in the low-speed range of gears 1-6, and maintaining steady throttle in the high-speed range of gears 7-12. The key technique is coordinating with the clutch: press it all the way down, shift gears smoothly, then release it without dragging. Don't force it when starting on a slope; shift back to a lower gear, stabilize, then proceed uphill. Familiarize yourself with the vehicle's sound—when the engine hums, it's time to shift. Regular maintenance checks on synchronizers and lubrication extend its lifespan. Efficient driving saves fuel.
