The gears are sticking in a manual car: is it down to the gearbox oil, the clutch hydraulics or the synchronisers? (Veikkola)

The gears are sticking in a manual car often in a way that provides the first clue as to the location of the fault. If only one gear is stiff, the suspicion falls on different parts than when all the gears are stiff. The engine temperature, the car’s movement and the feel of the clutch pedal also help to narrow down the cause before replacing any parts.

A single instance of a stiff gear change does not necessarily mean the gearbox is damaged. Make a note of which gear the problem occurs in, whether there is a rattling noise, and whether the problem improves as the car warms up. When a car is brought to the garage from the Veikkola area, the inspection begins with these observations and a test drive.

When the gears stick in a manual car when it’s cold

A gearbox that feels stiff when cold but returns to normal as it warms up is often indicative of the properties of the gearbox oil. The oil thickens in the cold, which slows down the interaction between the synchroniser rings and the gears. This symptom is most noticeable during the first few kilometres on a frosty morning, particularly when shifting from first to second gear.

However, cold weather alone does not explain the loud rattling noise or the gearbox repeatedly disengaging. During the inspection, the oil level, signs of leakage, the oil grade specified by the manufacturer and any metal content in the oil are checked. Using the wrong oil can impair the synchroniser’s operation, even if the oil level is correct.

The gears are sticking in a manual car in all gears

If all gears become difficult to engage whilst the engine is running, this indicates that the clutch and its operating system should be checked. The clutch may not disengage completely, in which case the engine will drive the gearbox input shaft whilst the pedal is fully depressed. In this situation, reverse gear may grind and first gear may feel particularly difficult to engage when the car is stationary.

In a hydraulic system, the cause may be low fluid levels, air in the system, or a leaking master cylinder or working cylinder. In a cable-operated clutch, check the cable and its adjustment. A mechanical fault in the clutch plate, pressure plate or thrust bearing can produce the same symptom, so the feel of the pedal alone is not sufficient to determine the correct repair method. Further information on distinguishing between symptoms can be found in the article clutch slippage and an abnormal engagement point.

A comparison carried out with the engine switched off often helps to distinguish between a problem with the clutch disengagement and a fault within the gearbox itself.

A gear that sticks suggests a synchronisation issue

If only second, third or some other single gear is stiff to engage, both when the engine is cold and when it is warm, worn synchroniser rings may be the cause. Synchroniser rings equalise the rotational speeds of the shaft and the gear before the gear engages. A worn part does not do this quickly enough, meaning the gear requires a slower movement than usual or causes a rattling noise.

Faulty synchronisation may become apparent when a gear engages following a half-throttle manoeuvre or a gentle double-clutch. This method may serve as a test, but it does not repair a worn part. Pressing the gear lever forcefully increases the load on the shift forks and clutch teeth.

Checking the clutch hydraulics and gearbox oil

The driver can check for any fresh leaks visible underneath the car, as well as the level in the brake or clutch fluid reservoir, in accordance with the car’s owner’s manual. In many cars, the brakes and clutch share the same fluid reservoir. A significant drop in the fluid level requires the source of the leak to be identified; simply topping up the fluid will not rectify the fault.

Checking the gearbox oil usually requires lifting the car until it is horizontal and opening the filler plug. The type of oil should be selected according to the car manufacturer’s specifications. Universal oil is not suitable for all synchronised gearboxes. Information on car maintenance and road safety can also be found at From Traficom’s pages for motorists.

When should you take your car to a garage in Veikkola?

Book an inspection if the gearbox is making a grinding noise, the clutch pedal sinks lower than usual, there is fluid leaking from under the car, or the gear won’t stay engaged. You should stop driving if you cannot engage a gear reliably or if the car tends to move off even when the clutch pedal is fully depressed. A fault like this can make it difficult to stop and set off in traffic.

STS Evitskog will investigate symptoms relating to the manual gearbox during a test drive and check the clutch operating system, the gear selector mechanism, the mountings and for any oil leaks. The workshop is located at Kylmäläntie 350, 02540 Kirkkonummi, so it’s a short journey from Veikkola. You can arrange a time and the details of the inspection the repair services page through.

A clear description of the fault will speed up the diagnosis. When booking your appointment, please let us know whether the symptom occurs when the car is cold or warm, whether it affects one or all gears, and whether the situation changes when the engine is switched off. With this information, the mechanic can focus the inspection on the oil, the clutch hydraulics or the internal parts of the gearbox without replacing parts unnecessarily.