What Causes Dual-Clutch Transmission Overheating?
3 Answers
Dual-clutch transmission overheating occurs due to constant gear shifting combined with low vehicle speed, which leads to excessive heat buildup in the clutch plates. The dual-clutch transmission (DCT) is a common type of automatic transmission that structurally resembles a manual transmission, but with an additional clutch set and gearshift control mechanism. The primary function of DCT is to ensure smooth vehicle starting, reduce impact loads on transmission gears during shifting, and prevent drivetrain overload. In conventional vehicles, gear changes are achieved through clutch disengagement and engagement, which temporarily interrupts power transmission during the transition.
I've been driving for twenty years and currently drive a dual-clutch vehicle. The most common cause of transmission overheating is crawling at low speeds in traffic jams, where the clutch is constantly in a semi-engaged state, generating heat through friction. This is especially problematic in summer when the engine compartment temperatures are high. Aggressive driving can also easily lead to overheating, such as frequent rapid acceleration and hard braking, which causes the clutch to engage and disengage multiple times within a second, generating high temperatures. Prolonged uphill driving without downshifting or carrying excessive loads can also overload the transmission. I know several dual-clutch drivers who have experienced premature clutch disc wear due to poor driving habits, all of which can easily trigger the overheating protection mechanism.
During our automotive testing, we discovered that defects in the dual-clutch cooling system can easily lead to overheating. The transmission fluid itself serves a cooling and lubricating function. If there is insufficient fluid, degraded fluid quality, or blocked fluid passages, the cooling efficiency will significantly decrease. Insufficient heat sink area or poorly designed cooling oil channels are also common design flaws, especially noticeable in cramped engine bays of certain small-displacement turbocharged engines. During one disassembly, we found that a damaged cooling fan caused poor air circulation, directly leading to a sharp rise in clutch temperature. Assembly precision is also critical, as excessive tolerances can cause abnormal increases in friction plate gaps and heat generation.
