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Transmission fluid is very important for the cooling and lubrication of your vehicle parts. Both manual and automatic gearboxes need tranny fluid because it works both as an oil and hydraulic fluid that cools and lubricates moving parts while helping with gear shifting.
Manual gear boxes can run on special oils like motor oil, gear oil or ATF and doesn’t require as much care as automatic gear boxes require. That’s because the main and only worry about manual gearboxes mainly is fluid contamination, which occurs over time.
Importance of transmission fluid
While the first automatic clutches used motor oil for lubricating, it’s not ideal for today’s modern vehicles. This is mainly because the extra gears in today’s vehicles produce lots of heat that needs a more specific fluid, automatic transmission fluids (ATF), for its major functions.
Gear mechanisms need it for not only cooling, and lubrication purposes but also to maintain fluid pressure, as a gasket conditioner and to help prevent oxidation. While lubrication is necessary to keep parts moving smoothly, fluid pressure helps activate clutch bearings and plates while changing gears, it’s necessary to keep the gearbox cool and prevent it’s possible overheating.
This is necessary because a heated gearbox eventually leads to clutch failures. The increased working temperature leads to the breaking down and contamination of the ATF. This is why you have to choose the best tranny fluid that takes care of all these functions when you run your car.
Best transmission fluid
Regarding the best gear case fluid for your car, it’s generally the ATF recommended by your car manufacturer. This should be mentioned in your vehicle’s owner manual and is the best for your vehicle because it’s specifically formulated to cater to your vehicle’s specific clutch needs.
Different ATF manufacturers add various additives to their fluids based on the specific gearbox model it’s formulated for. Various gearboxes have specific demands based on the way the car was built and it’s features.
Car manufacturers build their cars using specific materials and technologies for their specific car features. This is why even American cars can’t use the same ATF they use in Asian or European vehicles. So if you ever have to replace your gear case, you need to find the unit’s model and contact the manufacturer to find the best ATF for it.
But it works only if you use the right and best fluid for your vehicle and only if it’s in the right condition.
The fluid has to be changed every now and then, and you have to use the right fluid to avoid any potential serious damage to your clutch system. As you don’t have to change gear case fluids as regularly as you have to change motor oils, it’s obviously better to buy the best fluid available.
What does transmission fluid do?
Transmission fluid has two major responsibilities. It helps lubricate the bearing surfaces of the gearbox and also helps cool and reduce its heat. All this is possible only if you use the right fluid in your car with the precise viscosity befitting the concerned gear mechanism.
It’s also essential that the oil be durable enough to not break down when hot or under extreme pressure. The fluid also additionally serves as a viscous fluid that transmits power from the engine to the gear box in automatic clutch vehicles. There should also be sufficient ATF in the clutch because even driving with low or dirty gear fluid can lead to excessive wear and tear, and ultimately unexpected problems.
Besides, transmission fluid also deteriorates with time, like any other vital vehicle fluid. This is why it’s important that you check with your owner’s manual, and ask your mechanic for the best fluid maintenance to follow for your vehicle.
- FOR USE IN 95% of ATF VEHICLES INCLUDING MOST CVTs in operation with US registered light duty applications
- HIGH PERFORMANCE CONDITIONING AGENTS prolong seal elasticity to prevent leaks
- Formulated with full-synthetic base stocks and advanced additive technology to meet the challenging demands of automatic transmissions
- Enhanced anti-shudder protection for smooth shifting and maximum power transfer
- Engineered to help alleviate typical problems experienced by transmissions with over 75,000 miles such as leaks and rough shifts
- Greater frictional durability provides superior transmission performance
What happens without transmission fluid
Without any transmission fluid, your gearbox only ends up overheating and producing debris which eventually wears down its parts. By lubricating the gear case parts, the ATF not only keeps the gear lubricated and cool but also ensures its different parts do not get damaged.
It makes sure the gears don’t grind against each other, and this is when and how it ends up collecting a considerable amount of debris. This accumulated debris can affect your gear shifting and also acceleration because it hampers the fluid’s working efficiency. And as the friction the gear mechanism generates has to be counterbalanced by the ATF, bad transmission fluid ends up ineffectively dissipating heat.
Besides the loss of acceleration and problems with gear shifting, it’s in extreme cases that you experience a failed gear case because the gearbox runs without fluid or because you used the wrong fluid. The only remedy here is a gearbox replacement which is rather expensive because the gear case is a very complex piece of machinery.
Different types of transmission fluids
There are different types of tranny fluids available, containing unique additives and ingredients. These fluids are specifically formulated to reach specific fluid properties and performance for different vehicles. You can even choose your fluid between conventional and synthetic transmission fluids where the synthetic versions are twice as expensive as the conventional fluids. However, it’s worth paying extra because it is better in performance and is much better at resisting heat, friction, oxidation and cold better.
Instead of waiting until a clutch failure, it is better to periodically inspect the ATF’s level and condition. This is because though problems with the gearbox appear abruptly, it usually grows gradually. The first and most important sign of your problems with your gearbox is facing problems while shifting gears.
Your car breaking down in the middle of the highway is another sign of gearbox problems. If you notice that your transmission fluid level is low, then it is better to look for signs of a leak. It is also important that you check the fluid’s condition. If it is dirty or has a burnt smell, it means it is time for a fluid flush or fluid change. Gear fluid is otherwise red in colour, with a sweet smell when it’s fresh and in good condition.
How much transmission fluid do I need?
Now that you know all about the importance of transmission fluid in your car, and how to choose the best ATF for your car, you naturally wonder how much of fluid your car needs. Well, it’s important you pour the right amount of fluid into the dipstick tube because even too much of it can do more harm than good. Don’t assume that nothing will go wrong if you add a bit more fluid than required. Transmission fluid is a lubricant that ensures your car engine runs smoothly. It’s most important role lies in reducing friction in the gearbox so that you can easily change gears, and move your car backward or forwards as required.
As transmission fluid controls the clutch’s temperature and also reduces friction, it helps at protecting the metal surfaces from too much wear and tear. It is the right amount of transmission fluid in the gear case that increases the engine’s rotational speed and also helps condition the gaskets.
Signs to look out for
- If you are not sure how much is the right amount, well there are some signs you can look out for. While some signs are easily spotted, others require some more time and understanding.
- The first sign is your engine overheating. The engine should ideally run somewhere between 195 and 220 degrees, where the needle lies somewhere near the center of the gauge. Too much of fluid can reduce lubrication in the crankshaft, which in turn makes the engine hotter.
- The presence of puddle pools or drips under the gearbox may be due to either too much of fluid, or can even be a bigger problem. This is why it is better to have an expert mechanic take a look at your car if you notice drips or puddle pools.
Difficulty while shifting may also be due to foamy transmission fluid which is a result of too much fluid. This is because the excess fluid not only prevents proper lubrication and cooling but also ends up slowing down the rotating crankshaft.
- This is when air mixes with the excess fluid to create a foamy substance. This substance saturates the gearbox and leads to poor shifting, seal failure, high internal temperatures, and part pitting.
How to measure transmission fluid levels
If you don’t know how much of ATF your car needs, just pull out the dipstick while keeping the car running but parked. Then first clean the dipstick with a rag and then put it back into the transmission dipstick tube before pulling it out again. Be careful while doing this because tranny fluid can get really hot if your engine was running for a long time.
It’s based on the fluid level mark on the dipstick that you get an idea of how much more fluid the tube needs. Fill up the tube until the fluid reaches it’s ‘Fill’ line and do not let it go over the line.
If you are still not sure how much tranny fluid to add to the gear box, don’t take any risks. Just take your car to mechanics to take care of the problem without any complications.
How long does transmission fluid last
Like all other automobile fluids, even tranny fluids have an expiry date. With time contaminants in the fluid, the way you run the vehicle and heat break down the tranny fluid.
Not only does the fluid break down at different speeds, but different cars also have their own fluid change intervals. This is why it’s better to refer to your car’s user manual to find out what your car manufacturer’s recommended interval is.
Recommended change interval
While the transmission fluid change period differs between cars, depending on the car and truck, it is usually anywhere between 30,000 miles to more than 100,000 miles. There are even some latest cars that run on transmission fluid that last through the vehicle’s lifetime. This new generation fluids that last a lifetime are the synthetic ATFs which do not need to be changed. They are however only installed and used in new vehicles.
However, the Automatic Transmission Rebuilders Association recommends changing the fluid every two years or every 50,000 km. This, of course, may differ based on your driving habits.
How car usage affects the fluid change interval
As mentioned above, the car usage also determines the frequency for changing gear fluid. Tough driving conditions like excessive high-speed driving, driving in the hot climate, stop-and-go driving, snow ploughing, trailer towing, hauling and driving in cold weather takes its toll on the engine and gearbox.
This, in turn, means you have to top up your vehicle’s gear fluid. The tough driving conditions make your transmission fluid work harder and under higher temperatures than usual. This train leads to the fluid’s quick breakdown, which in turn means a quick fluid change. It’s when you don’t flush or change the fluid that your vehicle starts giving problems while driving like erratic shifting, overheating and slipping.
So you see, there’s no fixed answer to how long transmission fluid lasts. It all depends on your vehicle and usage. This is why it is better to have your gearbox serviced regularly to keep a tab on the fluid levels and to ensure your gear system is free from harmful, engine damaging contaminants and chemicals.
Transmission fluid flush systems
Some mechanics have flush systems that force out old fluid to pump in new fluid instead of letting the old fluid drain out. It’s during a transmission fluid flush that all debris that accumulated at the bottom of the pan is eliminated before pouring fresh and new transmission fluid into the car.
However, some manufacturers like Honda do not recommend a fluid flush for their cars. So make sure you check your user’s manual to ensure a flush is safe for your vehicle and if not, it’s better to just change the fluid.
Some automatic gear mechanisms even have filters that have to be cleaned or replaced while changing fluids. So make sure the mechanic knows the right procedure for your vehicle lest you end up doing more harm than good to your vehicle.
Ultimate Guide for Transmission Fluids
Last update on 2023-09-10 / Affiliate links / Images from Amazon Product Advertising API