What Causes the Abnormal Noise in Dry Dual-Clutch Transmissions at Low Speeds?
2 Answers
Dry dual-clutch transmissions produce abnormal noises at low speeds due to the sound generated by the shifting fork during gear changes. Below is a detailed introduction to dry dual-clutch transmissions in automobiles: Working Principle: The working principles of dry and wet dual-clutch transmissions are fundamentally similar, both utilizing two clutches that alternate operation. The difference lies in the medium connecting the driving and driven plates. Wet dual-clutch transmissions primarily rely on oil, whereas dry dual-clutch transmissions mainly depend on air. Basic Structure: In wet clutches, the two sets of clutch plates are housed in a sealed oil chamber, with the transmission oil absorbing heat by immersing the clutch plates. In contrast, dry clutches do not have a sealed oil chamber for their friction plates and rely on air cooling for heat dissipation.
I've driven several cars with dry dual-clutch transmissions, and the clunking noise at low speeds is quite annoying. The main reason is the increased clearance due to clutch disc wear, especially during frequent semi-engagement in city traffic jams—the friction plates can overheat and deform, causing noise. Additionally, aging or leaking seals in the hydraulic actuators can lead to unstable oil pressure, making the shifting mechanism produce abnormal sounds. If the springs in the transmission's synchronizer fatigue and break, there can also be a metallic clashing noise when shifting gears. When driving, remember to switch to manual mode in congested areas to reduce frequent shifts between 1st and 2nd gears. Once, I noticed abnormal noises and went for a checkup—it turned out I had to replace the clutch three-piece set to fix it. Now, during every maintenance session, I ask the mechanic to focus on inspecting the transmission mount bolts.
