Gearbox and clutch
Gears hard to engage or grinding: causes and what to do
If gears are hard to select or grind when changing on a manual car, the most common cause is a clutch that does not fully disengage, because of the hydraulic release or wear. Other frequent causes are low or old gearbox oil and worn synchromesh on a particular gear.
Check without hurryGearbox and clutch
Reviewed by Daniel Morales, founder of Reprorace SL, on
Is it serious? Can I keep driving?
Usually not urgent, but do not ignore it. It is rarely urgent, but do not force it: grinding wears the gearbox. If suddenly no gear will go in or the pedal stays down, do not keep driving.
A careful, general answer: only someone who inspects the car can say whether it is safe to drive. When in doubt, stop somewhere safe and call for assistance.
Most likely causes
- Clutch not disengaging: air or low fluid in the hydraulic release, or a dragging disc.
- Gearbox oil: low because of a leak, or degraded.
- Worn synchromesh: one particular gear grinds, often second or third.
- Cables or linkage: a stretched cable or a broken mount puts the lever out of position.
Listed from more to less common in general; on your car they may be different. A fault-code reading and a check at the garage confirm which one it is.
To understand it better: How often should you run diagnostics on your car? Can I diagnose my car myself?
Car system: Transmission
What you can check yourself
Notice whether one gear or all of them grind, and whether it happens cold or hot.
Make sure you press the clutch all the way down and a floor mat is not in the way.
If the clutch has its own reservoir, check the level with the car parked.
Look for oil stains under the gearbox area.
Safe checks only: with the engine off and cold whenever you look under the hood, without taking anything apart and without touching hot or moving parts.
Related fault codes
This symptom is usually mechanical and does not always store a generic fault code. Even so, reading the faults of every control unit helps to rule out other problems and to reach the garage with data.
How the ECO-LITE helps diagnose it
Plugged into the OBD socket, the ECO-LITE reads the fault codes of the control units that answer, with the freeze-frame data captured when the fault happened, and shows live data on your phone or computer. With your permission, your garage can see them remotely before you bring the car in.
What to look at here: this symptom is mechanical; the reading rules out other faults and, on some cars, shows the clutch switch and the detected gear.
Frequently asked questions
Why does reverse grind?
Reverse on many gearboxes has no synchromesh: wait a second with the car stopped and the clutch down before selecting it.
It only grinds when cold. Is it serious?
When cold the oil is thicker and some gears are stiffer. If it goes away once warm it is rarely serious, but have the oil checked.
Will an oil change fix it?
If the oil was low or degraded, it can help a lot. If the synchromesh is worn, it will not.
Keep reading
- Transmission: how it works and what fails
- Slipping clutch: symptoms, causes and what to do
- Automatic gearbox jerks: causes and what to do
- Noise when turning the steering wheel: what a click or a creak means
- Car symptoms: what they mean and what to do
- Check engine light on: what to do
- How to read and clear your car's fault codes
- OBD fault codes: what each one means