Some routine service actions such as changing the engine unit oil may seem obvious and very important, while others such as changing the gearbox oil from its Kia Optima may seem to be less natural. Nevertheless, make no mistake, changing the gearbox is just as important as changing the engine unit oil. This guideline will show you the function of the gearbox oil, then, why it is necessary to replace the gearbox of your Kia Optima, and at last, how to replace the gearbox oil of a Kia Optima .

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Role of gearbox oil on a Kia Optima

So we start our guideline with the function of gearbox oil on a Kia Optima. The objective of this short introduction is to make you understand the interest of this fluid which ensures the good functioning of your car. The gearbox of your car has the objective to demultiply the power transmitted by the engine unit and send it back to your wheels . It is made up of pinions and gears that will allow the wheels to rotate at different speeds depending on the curves and the gear engaged. It will function with the help of an axle and a differential. All these auto parts will need to be highly lubricate to function accurately, limit friction and tolerate the high temperatures built by the engine unit and friction. Your transmission oil has a high viscosity and will prevent the formation of filings or gear breakage, so it is essential to the correct working of the gearbox.

Why replacing the gearbox oil from a Kia Optima?

Now we’ll see what’s the point of draining the gearbox oil of your Kia Optima?

Benefit of gearbox oil changing Kia Optima

There are some concerns to replace the gearbox of your car frequently, we will list them and outline them below:

  • With time, the oil will lose its viscosity due to friction and temperature rise, which will result in less lubrication of the gears and pinions and therefore risk to break some of them.
  • Same as viscosity, time and temperature rise will lower the oil resistance to the engine unit temperature, So it will fluidize much more easily when the engine heats up, which is not good for your gearbox.
  • Accumulation of metallic residues: Finally, regardless if you always have a quality oil, a gearbox is an element that wears out and releases iron filings with friction, the oil will pick them up and if it builds up too much these residues can get into gears and break them.

When to do the gearbox oil replace on a Kia Optima?

If you want to do an automatic or manual gearbox oil change on Kia Optima or strong> the procedure is not the same, however, dealers do not give mileage suggestions to replace the oil in your gearbox, on the other hand when you do an intervention on the gearbox it is beneficial to replace it, otherwise here are the factors to make you take into consideration doing this oil replace.

Oil replace for manual gearbox Kia Optima

  • Gears are jumping: you are probably missing oil and you might have a gearbox oil leak, please see our article on gearbox leaks on Kia Optima for more info.
  • The gearbox cracks when you switch gears: The oil has absolutely lost viscosity and is too fluid, so the gears get stuck.
  • Difficulty to shift gears: Same issue as just before, the oil is absolutely too fluid.

Automatic gearbox oil replace

  • A slow start from the neutral position to the first one: generally a viscosity issue.
  • Difficulty or even impossibility to shift gears: Lack of oil

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How to replace gearbox oil of a Kia Optima?

Finally, to finish this article, we will show you you how to empty the gearbox oil of your Kia Optima , it’s easier than you might believe, here are the few steps to stick to to do it accurately:

  • Heat your Kia Optima for about 10 minutes to get a fluid oil, place it flat on 4 stands.
  • Install a drain pan under the drain plug, open it, and clean it well because it will probably gather filings.
  • Let all the oil run out until it’s all gone.
  • Replace and tighten the cap, then fill with a syringe through the filler cap with the manufacturer’s recommended dose

If you need more tutorials on the Kia Optima, go to our Kia Optima category.