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Transmission fluid is not checked very often by most car owners, whether they drive an automatic or standard car, yet it’s one of the easiest things to check and could be critical in catching a problem early and saving you money.
Read through this article to see what transmission fluid is, how to top it up, and why you should make sure there is always enough of it.
What is transmission fluid?
Transmission fluid, or ATF (Automatic Transmission Fluid), is a lubricating fluid that is somewhat similar to engine oil. It goes (no surprises here) in the transmission to keep everything lubricated and working properly.
The first thing you should know about transmission fluid is completely trivial, but may shock you if you’ve never worked with the stuff before: it stinks! Like, really, really smells bad. The smell of transmission fluid could perhaps be compared to BO mixed with rotting food, and, due to its nature, if you get it on you, it ain’t coming off for a while. So, basically, don’t get any on you, or wear PPE when you’re working with it if you think that might happen.
It’s made up of many different additives and, although it may contain it to some degree, shouldn’t be considered as an oil. It’s used for lubrication, as a hydraulic fluid for clutch engagement, as a corrosion inhibitor. It must be compatible with all electrical components with low conductivity.
Transmission fluid is also dyed red. This allows you to gauge its condition. If, when you’re checking it, the red seems vibrant, there is no problem. But, if the color appears to be more burnt, then it’s time for a change.
Potential things to watch out for
Although you could have too much transmission fluid in your car, the more likely situation is that you will begin to run out. This will usually be due to slight leaks around the transmission.
Watch out for the following signs, as they may indicate a problem.
- Vehicle lurches under gear changes.
- A transmission fluid puddle underneath the car after it has been sat for a time.
- Dashboard indicators. Modern cars will often have sensors wired into the transmission to let you know if the level is getting too low, or there’s a problem with the transmission of some kind.
What to do next
If one or more of these things seem to be happening to you while you’re driving, then there will be a problem of some kind with the transmission. This won’t necessarily be due to the level of transmission fluid being low, but you should hope it is – anything else may require a transmission rebuild, which would set you back a few thousand dollars.
Checking the transmission fluid level is a very simple task – we’ll walk you through it quickly now.
How to check the fluid level
- Make sure the car is parked on level ground. If the ground is sloped, then your readings will be skewed. Open the hood.
- Note that some newer cars measure the level of oil electronically. Everything’s electric these days! If this is the case, all you need to do is scroll through your dashboard until you find the transmission fluid level setting, which should let you know. You may need to consult your owner’s manual to find how to do this.
- Most cars, though, use the traditional dipstick approach. In the same way as to how you check your engine oil level, the dipstick shows the level of fluid in the transmission. It’s a crude yet very effective technique.
- Take a rag in one hand and pull the transmission fluid dipstick out using its handle. If you aren’t sure which one the transmission fluid dipstick is, consult your owner’s manual and look for a diagram of the engine bay.
- The dipstick should be coated with a translucent, red fluid. Using the rag, wipe it clean, and then put the dipstick back into its slot. Pull it out again, and look at it.
- The transmission fluid should be between the two marked points on the dipstick. If it’s too high, there is too much in there. If it’s below the bottom marking, there isn’t enough, and it’s time for a top-up or complete replacement.
If the transmission fluid looks a “burnt” color, or if it’s gone milky or has air bubbles in it, you are likely to need to take it to a specialist. Somehow, the transmission fluid has become contaminated. The cause of this needs to be fixed as soon as possible.
How to top up the transmission fluid
Firstly, make sure you have the right type of transmission fluid. This will probably be printed on the cap. Alternatively, you’ll find it in the owner’s manual or by looking up the vehicle information online. Using the wrong type of ATF could cause serious damage to your transmission.
You’ll also need a funnel.
- Take the transmission fluid and the funnel and go to the car, with the hood open and the dipstick removed.
- Put the funnel in the slot that the dipstick usually sits in and add a small amount of transmission fluid.
- After this, remove the funnel and the ATF and set them to one side. Use the dipstick to measure the level of fluid in the transmission.
- Keep on repeating this until the level is between the two markers.
- Start the car and run through all the gears, including neutral and reverse. This will allow the fluid to lubricate the whole system and give an accurate reading for you. Leave the engine to idle for a few minutes.
- Recheck the level of fluid, using the dipstick. It should still be within the two markers. If this is the case, you’re all done.
If the fluid level has dropped dramatically, you have a bigger and deeper problem than just old fluid. You’ll need a professional to look at it and, unfortunately, it’s not going to be cheap. If it has only dropped a little bit, simply top it up and repeat the process.
It’s highly recommended to continue checking the fluid level over the next few hundred miles you do. There may be a slow leak. Again, this will need to be looked at by a specialist if it is the case.
Checking and topping up your transmission fluid isn’t too tricky, and hopefully will save you a bit of money, instead of taking your car to an auto shop. We hope you found this article useful!