What Happens if I Put the Wrong Transmission Fluid in My Car?

Car transmissions are delicate mechanisms.

Each car has its own recommendations from the manufacturer on which transmission fluid your car needs.

Some transmission fluids are very incompatible with different transmission types as they use different additives in the fluids. Your car transmission needs the correct fluid, as specified by your car manufacturer, to run correctly and to the fullest length of life.

While it’s not uncommon for someone to mix up which fluids should go in their car, putting the wrong transmission fluid in your car could be your vehicles fast pass to an early grave.

Types of Transmission Fluid

There are several different variables to take into account when it comes to transmission fluid. You first must know if your car requires automatic or manual transmission fluid. Then determine if your car is an automatic transmission if it has a continuously variable transmission. You should always follow your manufactures specifications on which fluid is right for your car.

Related: What is Transmission Fluid?

Automatic Transmission Fluid vs. Continuously Variable Transmission Fluid

Hand pouring transmission fluid through funnel as for the good car maintenanceAutomatic Transmission Fluid (ATF)

Automatic transmission fluid is fluid that is used in cars that have automatic (self-shifting) transmissions. This fluid is optimized for use in automatic gearboxes that consist of a hydraulic pump, gears, disks, and bands.

Continuously Variable Transmission Fluid (CVT)

A continuously variable transmission is a type of automatic transmission vehicle. This type of transmission can change seamlessly through a continuous range of gears. It is able to do this by running on a series of pulleys connected with a steal band, rather than a fixed set of gears. CVT transmissions require CVT fluid. This fluid has friction modifiers that allow the belts to grip the pulleys.

Related: 5 Types of Transmissions

What  Happens if You Use the Wrong Transmission Fluid

The most common situation where the wrong transmission fluid is used is in the case of using automatic transmission fluid in place of variable transmission fluid and vice versa. Adding ATF to a to a CVT will eventually result in the death of your transmission.

Warning Signs

There are a few warning signs that you can look for to indicate that you have used the wrong fluid in your transmission including:

  • Strange engine sounds such as clunking
  • Stalling after changing gears
  • Gears that won’t shift
  • Rough shifting
  • Gears that slip
  • Clutch locking up

So How Long Do I Have?

If you accidentally put ATF into a CTV the rate at which it will die is directly related to the ratio of fluids. In a CVT transmission, it is impossible to drain all of the CVT fluid. If you have accidentally added ATF, your transmission would then contain a mixture of ATF and CVT fluids. Your CVT transmission will still function for a period of time since it is a mixture of both fluids and there will still be enough friction for the CVT transmission to work for a while. Eventually, however, permanent damage will occur and you have to rebuild your transmission.

Related: Transmission Rebuild vs. Replace

What to Do If You’ve Used the Wrong Transmission Fluid

If you have used the wrong transmission fluid you will need to remove that fluid as soon as possible to try to minimize the amount of damage to your transmission. If your car has already been driving with the wrong fluid for many miles it is possible you will need to replace your transmission outright as too much damage has already been done.

Transmission Flush vs Transmission Change

Transmission Change

In a transmission change (sometimes known as transmission service) the transmission fluid pan is drained and the filter is replaced. Transmission changes do NOT remove all of the transmission fluid from the car and often times up to half of the fluid can remain. If you have contaminated your transmission fluid with the wrong fluid, this is not going to be the right choice for your car as the new fluid will simple get contaminated by the remaining old fluid.

Transmission Flush

Drain the old used transmission fluid before adding the new as for the good car maintenanceA transmission flush is where AL of the old fluid from your transmission is removed via a cooler line flush machine or pump inlet flush machine. Once all of the old fluid has been removed, entirely new transmission fluid is added. In the situation where you have put the wrong transmission fluid into your car, a transmission flush is going to be a better option than a transmission change.

Related: Benefits of a Transmission Fluid Flush

Transmission Maintenance and Repair with AAMCO Colorado

Having transmission problems? Transmission contaminated? Not sure which transmission fluid is right for your car? Your local AAMCO Colorado transmission technician can help with your transmission repair and maintenance needs.

Schedule an appointment to bring your car to your local AAMCO Colorado location today.

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