Automatic gearbox problems: how to recognise the five warning signs

You usually notice it first through small changes in how the car drives: a jolt that was not there before, a noise or a car that responds more slowly. A healthy automatic changes gear smoothly and without noticeable noise. According to viaBOVAG, the consumer site of the Dutch motor trade association, an automatic should not jerk when changing gear and no noises should come from the gearbox.

A warning sign does not mean the gearbox is broken. An automatic gearbox is a combination of gears, clutches, hydraulics and electronics. The transmission fluid lubricates and cools the parts and transmits the pressure that closes the clutches. That fluid ages with heat and use. According to gearbox manufacturer ZF, oil ages faster than normal at very high operating temperatures. Old fluid can cause shifting complaints without anything being broken.

The cause can also lie outside the gearbox. A worn engine mount, a driveshaft or an engine that misfires can feel very much like an automatic that jerks. That is why a proper diagnosis is the first step, not a flush or an overhaul straight away.

These are the five signs we see most often in an automatic that needs attention. The table shows what each sign can mean. Below it you can read more about each one.

Overview by Autobedrijf Willemsbrug. A table does not replace a diagnosis.

1. Your car jerks or shudders when pulling away or changing gear. This is a common sign. Sometimes it only happens when the engine is cold, sometimes it stays. The cause can be old or contaminated fluid, a low fluid level, wear of the clutches inside the transmission or a problem with the control system. A worn engine mount also causes a thud when you pull away. Does the gearbox jerk mainly when it changes gear? In our article automatic gearbox jerking when shifting you can read what to do in each situation and whether you can keep driving.

2. You hear unusual noises. An automatic gearbox should not make any noticeable noise. If you hear a clunking, whistling, whining or humming noise, have it checked. The cause can be inside the gearbox, for example a bearing or the torque converter. A torque converter is the fluid coupling between the engine and the gearbox in a conventional automatic. The noise can also come from a wheel bearing or a driveshaft. Pay attention to when you hear it: only when changing gear, at a certain speed or also when the car is stationary.

3. The automatic slips or does not change up. You press the accelerator, the engine revs harder, but the car hardly speeds up. Or the gearbox unexpectedly changes down or stays in one gear. When it slips, the clutches inside the gearbox are not transmitting the engine’s power properly. This can be caused by too little or old fluid, but also by wear. If it is wear, a flush will not solve the problem. Do not put off having it checked, because driving on with a slipping automatic creates extra heat and wear.

4. Your car is slow to respond to the accelerator. Does it take a moment before the car speeds up when you press the accelerator? Then the hydraulic pressure in the gearbox may be too low. The engine management or the accelerator pedal sensor can also play a part. A related sign is a kickdown that no longer works: the gearbox does not change down when you push the accelerator to the floor to overtake.

5. A warning light comes on or the car goes into limp mode. Is the engine warning light or a gearbox warning light on, or has the car switched to an emergency programme? Then the control unit has detected a fault. In this limp mode the gearbox often stays in one gear to protect itself. Only drive on if it is safe to do so, and have the fault codes read as soon as possible. If the car tells you to stop, park it in a safe place. You can read more about this light on our page engine warning light on: meaning and diagnosis.

The signs and the solution depend on the type of automatic in your car. There are four main types. They work differently and need different maintenance. The overview below follows the explanation by the ANWB, the Dutch motoring organisation, and viaBOVAG.

Source: ANWB and viaBOVAG, with additions by Autobedrijf Willemsbrug.

On a conventional automatic, a flush can be worthwhile if the complaint is caused by the fluid. On a DSG or another dual-clutch automatic, we change the oil according to the manufacturer’s instructions. On an automated manual, such as the Dualogic in many Fiat 500 automatics, a flush is not the solution. There the problem is often in the clutch or in the hydraulic unit that controls the clutch and the gear changes.

Not sure which type of gearbox you have? Call us with your registration number on +31 10 479 00 00. We can usually look up straight away which transmission belongs to your car.

There are a few things you can check yourself. They help with the diagnosis and save time in the workshop.

1. Note when it happens. With a cold or warm engine, when pulling away, at a certain speed or when overtaking.
2. Look under the car. A red, pink or brown patch under the front can be transmission fluid. Our page fluid under the car shows what each colour means.
3. Watch the dashboard. Note which light or message you see and whether it stays on or goes out.
4. Use your nose. A sharp burning smell after driving can point to overheated fluid or a slipping clutch.
5. Look up the service history. Has the transmission fluid ever been changed or flushed? Is there anything about it in the service book or on old invoices?

Many modern automatics have no dipstick. In that case we check the fluid level in the workshop, at the correct fluid temperature and following the manufacturer’s procedure.

We start with the complaint, not with the solution. A fault code alone is not enough, because not every mechanical or hydraulic problem shows up electronically. That is why we work in set steps.

1. Intake. You tell us what you notice and when. Your notes help here.
2. Test drive. If it is safe, the mechanic takes a short drive, with you or alone, to feel and hear the complaint.
3. Reading the fault codes. We read the engine and transmission control units for stored fault codes and look at live data such as fluid temperature and engine speed.
4. Inspection on the lift. We look for leaks, check the colour and smell of the fluid and the fluid level, and inspect the engine mounts and driveshafts.
5. Advice and quote. You hear what we have found and which treatment fits. You receive a quote in advance and we only carry out repairs once you have agreed.

You can read more about how we deal with faults on our page car diagnostics. Have you been advised elsewhere to replace the gearbox and are you unsure? Then you can have a second opinion with us for € 145, including up to one hour of investigation.

Maintenance or a flush helps if the complaint is caused by old or contaminated transmission fluid. It does not help with wear, a leak or an electronic fault. A flush is maintenance, not a repair.

Indication by Autobedrijf Willemsbrug. The diagnosis determines the advice for your car.

For a flush, also called a transmission flush or power flush, we connect a flushing machine according to the procedure that suits your transmission. This replaces a larger share of the old fluid than draining and refilling alone. We then fill the gearbox with fluid that meets the prescribed specification and set the level at the correct temperature. You can read how this works on our page automatic gearbox flush. The difference from a fluid change on its own is explained in gearbox fluid change or flush.

Prevention is better than cure. ZF, a major maker of automatic gearboxes, fills its gearboxes at the factory with what is known as lifetime oil, but still recommends an oil change after 150,000 km. According to ZF, shorter intervals are advisable for high-speed driving, towing a trailer or a sporty driving style. Which interval suits your car is explained in when to flush an automatic gearbox.

We investigate and maintain most common automatics: conventional automatics with a torque converter, including ZF gearboxes, DSG and S tronic gearboxes, other dual-clutch transmissions (DCT), EAT6 and EAT8 gearboxes from Peugeot, Citroën and Opel among others, Multitronic, Geartronic, Multidrive and various CVT systems. Whether a flush is possible and worthwhile for your transmission depends on the make, the model, the year, the transmission type and the service history. For each version we check which type of transmission and which maintenance procedure apply. Mercedes-Benz and Renault have their own page with information per gearbox type, and the price indications per make are on the page automatic gearbox flush cost.

You can find us at Boterdiep 11 in Rotterdam-IJsselmonde, close to Stadion Feijenoord (De Kuip). We are open Monday to Friday from 8.00 to 17.30 and on Saturday from 9.00 to 15.00. We work by appointment. For a quick question or check you can walk in without an appointment.

Follow the manufacturer’s service schedule first. The interval differs per transmission, year, fluid specification and use. With heavy use, such as a lot of city driving, short trips or towing, maintenance may be needed sooner. If the manufacturer gives no interval or talks about lifetime fluid, our own workshop advice is to have the fluid assessed at around 60,000 to 80,000 km. That is our advice, not a manufacturer’s requirement. If you notice one of the five signs, have the cause found first.

With a drain and refill, part of the old fluid stays behind in the torque converter, the cooler and the lines. How much depends on the transmission. With a flush, a machine replaces a larger share of the old fluid according to the prescribed procedure. Neither of them repairs serious wear.

There are several possible causes. Sometimes a fluid was used that does not meet the prescribed specification, or the fluid level was not set at the correct temperature. There may also have been wear already that a flush could not fix. You can read more in our article about problems after a gearbox flush.

The price depends on the car, the type of transmission, the amount of fluid and whether a filter or gasket is included. You receive a quote in advance for the agreed work and we only start once you have agreed. For comparison: according to the ANWB, a gearbox overhaul costs around € 2,500 including fitting.

That varies a lot with the type of transmission, driving style, load and maintenance. According to viaBOVAG, automatics can reach a great age without problems if they are maintained as prescribed. A fixed lifespan cannot be given.

No. A flush is maintenance, not a repair. If the complaint is caused by old or contaminated fluid, it can become less or disappear. A mechanical fault, a leak or an electronic fault needs a repair.

No. Cold fluid is thicker, so an automatic can change gear a little more stiffly for the first few minutes. If you feel a real thud, or if it continues once the engine is warm, have the gearbox checked.

No. Slipping creates extra heat and wear. At most, drive a short distance gently to the garage and avoid the motorway. If you smell burning or the car will no longer move, stop and have the car transported, for example through your breakdown service.

• ANWB: Versnellingsbak uitgelegd + Revisie en vervangen kosten (in Dutch)
• BOVAG (viaBOVAG): Occasion met automaat kopen? Hier moet je op letten (in Dutch)
• ZF Aftermarket: ZF Aftermarket product portfolio: transmissions (oil change)