What is the reason when the car's RPM goes up but the speed doesn't increase?
3 Answers
The reasons why a car's RPM increases but the speed doesn't go up are: 1. Burning of clutch discs; 2. Insufficient tightening torque of the friction plate clutch; 3. Transmission oil hasn't been changed for too long or damage to the hydraulic mechanism in the transmission; 4. Slippage of internal friction plates in the transmission; 5. Failure in the engine's electronic control system. Car RPM refers to the rotational speed of the car's engine. The car's tachometer is located on the instrument panel, symmetrically placed with the speedometer. Its functions are: 1. To promptly reflect the operating condition of the engine; 2. To allow the driver to better coordinate the transmission gear and throttle position; 3. To keep the car in a better working state; 4. To reduce consumption and prolong the engine's lifespan.
I've fixed quite a few cars with this issue, and it's mostly caused by clutch slippage, especially in manual transmissions. The engine RPM surges, but the clutch plates are worn too smooth, so the power can't reach the wheels, and the speed won't increase. It could also be a problem with the torque converter in an automatic transmission—low fluid or a broken seal reduces power transfer efficiency. Loose drive shafts, uneven tire pressure, or tire slippage can also cause this. Don’t overlook the electronic control system either—a stuck throttle or faulty sensor can make the engine rev high without delivering real power. Early inspection is crucial. I recommend checking the clutch pedal resistance monthly and topping up the transmission fluid before highway trips to avoid breakdown risks. I once saw a case where the owner ignored it, and the entire transmission ended up ruined, costing thousands extra. Getting it fixed promptly saves money and gives peace of mind.
Veteran drivers talk about this issue. I've driven all kinds of cars and experienced many situations where the RPM rises but the speed doesn't follow. The most annoying is manual transmission clutch wear, where the RPM spikes during gear shifts while the speed crawls. Automatic transmission problems are more complex—torque converter failures or aging drive belts can cause similar symptoms. Environmental factors also play a role, like tire slippage on rainy days where the engine revs but the wheels don't move. Driving habits matter too—avoid slamming the accelerator; smooth acceleration is better. I often remind friends to listen for unusual noises or vibration warning signs while driving and address them early. Safety first—if this happens on the highway, pull over immediately with hazard lights on. For regular maintenance, check the clutch and transmission fluid monthly, and extending their lifespan by a year or two is no problem.
