Allow your gearbox long life

Modern gearboxes are tough and durable. A gearbox that is not abused and is well maintained might well outlive the rest of a car's mechanical components.

The first commandment of gearbox care is to keep the box topped up with the specified oil to the correct level. A constant supply of clean gear oil or automatic transmission fluid is needed to prevent overheating and rapid wear.

On new vehicles the gear oil will normally stay where you want it - inside the gearbox. But as the gearbox ages, leaks can appear.

The only way to be sure the oil level is up to the required mark is to check it regularly, say once a year if there is no sign of leakage, and at least once every six months if you suspect there's a leak.

If topping up is needed frequently, there's a leak somewhere

Cleanliness is important. The slightest piece of grit in a gearbox is bad news.

Manufacturers stopped putting drain plugs on differentials when they discovered that more harm was done to the gears and bearings by grit getting in during the process of changing the diff oil than the good that came from fresh oil. The same danger exists with gearboxes.

Here are a few more hints to ensure a long and trouble-free life for your car's gearbox:

l Never overfill a gearbox. That is almost as bad as a low oil level. It will lead to overheating because the oil cannot do its cooling job efficiently in an overfilled box.

l The most common gearbox-related problem is "crunching" when shifting into gear.

This is often caused by the clutch not releasing completely when the clutch pedal is pushed in, something that can easily be put right by adjusting the clutch linkage.

l Never allow a car with a manual gearbox to be towed further than is absolutely necessary with its drive wheels on the ground.

With automatic transmissions, the prohibition on towing with drive wheels on the ground is even stricter. Always lift the drive wheels off the ground when a car has to be towed.

l Finally, don't bang the box into its gears. Firmly but gently "feel" it in, and don't indulge in drag racing.