How Do I Know if My Gearbox Fluid is Low? MILTA Technology

How Do I Know if My Gearbox Fluid is Low?

When it comes to maintaining your automatic or manual gearbox, the key approach to avoid costly problems is to take the preventive and not the reactive path. What we try to achieve is to emphasize how important it is to learn the basic gearbox maintenance schedule and stick to it. Regularly replacing and monitoring the gearbox fluids level and quality is mandatory. While the maintenance intervals for gearbox fluid are longer than that of engine oil, it is crucial that we don’t forget about them!

To help you avoid any problems during the service intervals, we have prepared a guide on recognizing the signs of low gearbox fluid levels and why you should never ignore those signs. Learning this information can both prevent bigger gearbox maintenance bills in the future and will make you a more confident car owner and driver. Let’s dive in!

The correct amount is crucial

Just like engine oil, the purpose of gearbox fluid is to lubricate all the moving mechanical parts within a gearbox, both manual and automatic. Gearbox fluid acts as a protective liquid that dissipates the heat of friction and prevents metal abrasion.

If there is no sufficient amount of fluid or if the viscosity of it is too low, the frictional heat can cause overheating, the excessive friction introduces metal shavings into the gearbox and soon enough a complete gearbox failure is certain.

How to recognize the signs of low gearbox fluid

Over time, all transmission fluids lose their viscosity and the ability to lubricate the moving mechanical parts inside the gearbox. But sometimes the signs of worn gearbox fluid can also be similar to those of low gearbox oil. Here is what to look for in both cases:

  • If you own an automatic, pay attention to any delays in shifting and irregular movements while driving. An automatic gearbox can suffer serious damage when driven with low oil levels or worn-out, old gearbox oil.
  • Cars with automatic gearboxes and low gearbox oil levels also tend to consume much more fuel.
  • With both types of gearboxes, manual or automatic, pay attention to any leaks and oil stains beneath your car. Your gearbox is usually positioned behind the engine so the oil stains should appear beneath the driver’s seat and not directly under the engine.

How to check the gearbox fluid level and quality

We would be lying if we said this is really simple. In most cases, we recommend that you visit a specialized gearbox service centre in order to properly assess the level and the quality of the gearbox fluid. However, some cars with automatic gearboxes do have a dipstick that makes checking the fluid level much more simple.

Automatic gearboxes:

1. If your car has a gearbox oil level dipstick then locate the gearbox oil container and dipstick under the bonnet. Consult the user manual if necessary.
Important: Some car user manuals also specify the procedure of checking the gearbox fluid level. Most manufacturers recommend checking the gearbox oil level at normal running temperature. They also recommend going through all the gears (PRND) at least 3 times before checking the oil level.
2. Take the oil dipstick and open the gearbox fluid container.
3. Insert the dipstick, wait for 5 seconds and inspect the fluid level on the engraved scale when you take it out.
4. Based on the reading, decide if you need to top-up gearbox fluid or not.
5. Wipe the dipstick against a clean cloth and observe the consistency, appearance and the smell of gearbox fluid. If you see small lumps, frothing, dark or almost black colour and if the oil seems “runny”, consider a visit to a service centre and a change.
Important: The gearbox fluid level can fluctuate based on the oil temperature. If you decide to top-up the gearbox oil, make sure you are using the same gearbox fluid that is currently in your gearbox. Do it in small increments and avoid overtopping!

Manual gearboxes:

Manual gearboxes do not have an oil dipstick. Manual gearbox oil changes are done in longer intervals and demand more mechanical knowledge and equipment (a car lift, for instance, a simple car jack will not suffice). If you experience problems with your manual gearbox, book an appointment
with your mechanic as soon as possible. There is not much you can do at home.

Can you top up the gearbox fluid level at home?

As we mentioned before, with certain automatic gearboxes you certainly can. But before you do, make sure you know exactly what you are doing. If you have any doubts about your capabilities, please take your car to an experienced service centre and let them do it. You can also learn from them and get the confidence and the knowledge you need to do it on your own.


If your car offers the possibility of checking the gearbox fluid level, then, by all means, do it on a regular basis. Checking the fluid level and examining the state of the gearbox fluid is the best practice for preventing unwanted gearbox issues. If your car does not allow you to do that without a car lift and specialized tools, then the best option is to ask your mechanic to inspect your gearbox and gearbox oil level at every engine oil replacement interval which is usually much shorter. Your mechanic will also notice any gearbox fluid leaks which can lead to trouble down the road.

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