Automatic Transmission Tips & Advice
Tips for getting the most out of your automatic transmission
Your automatic transmission can have up to 3,000 different parts. This complicated piece of machinery is remarkably tough and long-lasting if you consider the stresses and temperatures it works under.
With a bit of knowledge and just a few simple precautions, you can get years of trouble-free performance from your auto transmission.
Some of the more common questions that vehicle owners ask us:
The most important things you can do to prolong the life of your auto transmission don’t require any change in your driving habits. Yes, it’s better to avoid fast acceleration. You may want to shift out of D when waiting at a traffic light. But these things will hardly make a notable difference.
What you really need to do is pay attention to checking and changing your auto trans fluid and having it serviced once a year by a trained specialist.
If your vehicle is fitted with a dipstick for the automatic transmission fluid, it’s no trouble to check it whenever you check your water and engine oil. You can even top up your transmission fluid with very little effort. Just make sure you use the recommended fluid for the particular make and model that you drive. This is not an area where you should take chances or skimp on cost.
If you use your vehicle for towing or a lot of driving in mountain passes, you may want to install an auxiliary auto trans fluid cooler to prolong the life of your transmission.
The big thing to remember is that your auto trans is usually not included in a normal service – you have to ask for the automatic transmission to be serviced. Do this at least every 15 months or once every 25,000km, whichever comes first.
If ever you suspect that there may be something wrong with your auto transmission, don’t take chances – get your vehicle to a specialist repairer as soon as possible.
Because overheating is the main cause of automatic transmission failure, some people choose to install an auxiliary oil cooler for automatic transmission fluid.
Most automatic cars come standard with a separate heat exchanger for the transmission oil just below the radiator. Given the high temperatures you can find in a radiator, often just under the boiling point of water, a short cycle through this heat exchanger doesn’t reduce the temperature of the automatic transmission fluid all that much – only by about 10-20%. Still, with few exceptions, this does the job when you’re only doing everyday driving.
However, if you plan to tow a trailer, boat or caravan, it may be worthwhile having an auxiliary transmission fluid cooler installed.
This is because an automatic transmission takes extra stress when towing, and this raises the temperature in the transmission. Even at just a few degrees hotter than the temperature it was designed for, transmission fluid can become less viscous – not doing its job of lubrication as well as it should and reducing the lifespan of the auto trans.
Similar conditions can develop when you drive in mountains, in heavy traffic or at high speed on hot days.
An auxiliary cooler can keep transmission fluid at optimum operating temperature for longer. Typically, these coolers reduce the temperature by between a third and half from the time the fluid enters the cooler till the time it flows back into the transmission.
When you take your vehicle for a regular service, this usually does not include servicing your automatic transmission. You have to ask specifically if you want your auto trans serviced or repaired.
How often you have to do this depends on the make and model of your vehicle and how you use it. The auto transmission in a vehicle that is used for towing or that accelerates and decelerates more than usual will need attention more often.
The operating temperature is also a key factor. Automatic transmission fluid that may last for over 80,000km at 100°C may only last a quarter as long at 125°C.
Some vehicle manufacturers suggest you can go more than 100,000km with the same fluid, while others even claim to have developed automatic transmissions that never require fluid changes! Nevertheless, it’s a sensible precaution to have your automatic transmission fluid levels checked when you do it for your engine oil.
Experts suggest you get your auto trans serviced at least every 15 months or 25,000km. If it’s well looked after, your automatic transmission can last well in excess of 200,000km. On the other hand, transmissions that aren’t checked and serviced can fail not having done half that distance.
Most cars have a dipstick for you to check the fluid level in your automatic transmission. If your vehicle has one, checking it is easy. You may be out of luck, though, as some models don’t have such a dipstick and only a transmission specialist can check the auto transmission fluid level.
- Find the dipstick.
Your owner’s manual should show you where it is. Usually it’s behind the engine block, on the other side from the belts.
- Get the necessary equipment.
You need a rag and (if a top-up is required) a long, thin funnel and the right kind of fluid. It is very important that you find out exactly what kind of transmission oil should go into your car. They’re not all the same. Filling your transmission with the wrong kind could be about as bad as not having any at all and could lead to a major auto trans fault.
- Park your vehicle on a level surface.
This ensures your reading isn’t slanted by fluid pooling on one side of the auto trans.
- Check if your engine should be running or not.
Your owner’s manual should tell you. On some cars, the engine should be warm and running, while others are best checked warm, but not running. If it should run, put your vehicle in P and let it idle. Be careful when working under the hood – you don’t want anything of yours caught in the moving parts.
- Use the dipstick.
Pull it out, wipe it clean with the rag and put it back in its place, pushing down all the way. Pull it out again and check how much of the stick is covered in fluid. The level should ideally be between the two marks on the dipstick. Also look at the condition of the fluid itself. It’s usually red when new, going brown later. If it’s quite dark, you may need to service the transmission.
- Top up if necessary.
Use a long, thin funnel and pour the fluid into the hole, only about 250ml at a time. Let the fluid settle for a few minutes before gauging the level again. Be careful not to overfill the automatic transmission, as its correct functioning depends on having just the right fluid level. Too much and the transmission may develop problems.
- Replace the dipstick.
Make sure it’s all the way in and fits snugly. All done!
The short answer is to check your transmission fluid regularly. It’s easy enough to do and may save you lots of time and money.
As to changing it… opinions vary greatly. Some vehicle manufacturers claim you never have to do it, others suggest a very long time between changes – upwards of 60,000km. Based on some of the transmission damage we see at A Automotive Services, we suggest you change your auto transmission fluid about every 25,000km.
As much as nine out of ten faulty transmissions are the direct result of overheating.
The fluids being used are getting better, but they have to handle incredible rigours inside an automatic transmission, where friction generates tremendous heat. Most of these fluids are designed to operate well at about 80°C. This temperature is normal for cars moving at even speed with no undue stress. However, under fast acceleration or when towing, the temperature in your transmission can rise sharply, causing transmission fluid to work less efficiently and reach the end of its useful life quicker.
What happens at high temperatures is that the auto trans fluid oxydises – sometimes even giving off a burnt smell. As it gets hotter, the fluid becomes a less effective lubricant, causing wear in the transmission. The fluid itself could leave a varnish-like film on metal surfaces, further hampering performance. At even higher temperatures, rubber seals harden, which can lead to leaks. If this happens, you’re looking at an expensive repair job.
There will usually be indications of a fault with your automatic transmission long before you run into serious trouble. So you have to be aware of what to look out for.
- Feel the motion
One of the hardest changes to spot is if your transmission simply doesn’t feel the way it used to, as the change could be gradual. Be on the lookout for gear changes that happen later or take longer than you expect. They may even be jerky, not as smooth as they should be. A shuddering gear change is always cause for concern.
Listen to the revolutions of your engine. If the engine revs between gears, that’s a sign that something is wrong with the automatic transmission. If the revolutions seem to be out of sync with how your vehicle moves, pay close attention. For instance, when revs are high, but the vehicle moves too slowly or not at all. Unexpected, unusual noises could be a telltale sign of trouble too.
Sometimes faults show themselves through a burnt smell. This could be the transmission fluid.
- Failsafe mode
If your vehicle is equipped with a failsafe mode, this may engage. Failsafe keeps your vehicle in one gear if there is a problem with the transmission, so you can at least keep moving. If this happens, drive as little as possible and get specialist attention as soon as possible.
Transmission faults can be hard to identify. So if you spot anything that causes worry, it’s best to get your vehicle to the professionals at A Automotive Services as soon as possible.