Car won't go into gear: what a manual gearbox is telling you

What it means

Inside a manual gearbox the gear pairs are always meshed. Moving the lever pushes a selector fork, which slides a synchronizer sleeve toward the chosen gear. A blocker ring first drags the gear to the shaft's speed, and only when the speeds match can the sleeve slide over the gear's dog teeth and lock it. That resistance is what you feel through the lever.

For all of this to work, the clutch has to disconnect the engine completely while the pedal is down. If it drags, or a synchronizer ring is too worn to match the speeds in time, the gear resists or crunches.

Common causes

• Clutch drag, where the clutch does not fully release: air or a leak in the hydraulics, a stretched cable, a worn release bearing or a warped disc
• A clutch pedal that no longer travels its full stroke, because of a floor mat or a bent bracket
• A worn synchronizer ring, if only one gear grinds
• Gearbox oil that is old or the wrong grade, if selection is stiff or notchy when cold
• Worn linkage or a stretched cable to the gearbox, making the lever vague
• Dog teeth lining up tooth on tooth, if the lever will not go in until you release and try again

What to do now

1. Note which gears resist: every gear, first and reverse at a standstill, or one gear only, and whether it is worse cold or hot.
2. Check that nothing, such as a floor mat, stops the clutch pedal travelling its full stroke.
3. On a hydraulic clutch, check the fluid reservoir. Many share it with the brakes.
4. If the lever will not go in, ease off, let the shaft turn a fraction, and try again.
5. If reverse resists, stop fully, press the clutch all the way down, wait a few seconds and try again.
6. Tell the workshop whether it is every gear or one gear.

Which gear, and when?

• Grinding into every gear, or first and reverse hard to select at rest: clutch drag, meaning the clutch is not fully releasing
• Grinding into one specific gear, the others fine: that gear's synchronizer ring
• Stiff or notchy when cold, easing as the gearbox warms: often the oil, either the wrong grade or old
• The lever goes in on the second try: possibly dog teeth lining up tooth on tooth, so ease off and try again
• A brief clash selecting reverse while the shaft is still turning: can happen on a reverse that is not synchronized, but repeated grinding is not normal
• The clutch pedal stays down or comes up slowly: a failing master or slave cylinder, so stop driving

What people often get wrong

That grinding into reverse is just how some cars are. A brief clash can happen on a reverse gear that is not synchronized, but repeated grinding is not normal on any car. It can mean incomplete clutch release, incorrect adjustment, hydraulic trouble or internal wear.

When the car must go to a workshop

Have it checked, and ask for the release system to be looked at first, the hydraulics, the cable and the pedal travel, before anyone opens the gearbox. Mention any leak you have seen at the driveshaft seals or the gearbox's rear seal: a low oil level is the one thing that will destroy a gearbox quickly.

Read next

• Clutch slipping: how to tell, and why it won't improve
• Soft or spongy brake pedal: why it is urgent
• P0700: a fault in the transmission control system

This page is general information and does not replace a professional assessment. Symbols, codes and behaviour vary between makes. Always check the handbook for your own car.