Is Transmission Fluid Lifetime?
Is Automatic Transmission Fluid Lifetime: It mostly depends on who you ask and their point of view. New cars are coming out of production lines with “no service” transmissions or lifetime transmission fluids, whatever “lifetime” means.
Short answer is: No, automatic transmission fluid can not be and it is not lifetime, nothing is lifetime.
Long answer is below.
What Does Automatic Transmission Fluid Do?
Automatic transmission fluid lubricates transmission and transfer engine power to transmission using a torque converter and clutch plates. An automatic transmission will not work without oil, it will not shift gears and damage itself. Usually there is about 7 liters of transmission fluid, based on type and size of transmission.
Automatic transmission fluid properties include, viscosity, temperature performance, viscosity and volatility. Number one enemy of transmission fluid is heat, and there is a lot of heat inside an automatic transmission. Transmission oil coolers installed on cars prolong transmission fluid lifespan, up to a certain point.
(Manual transmission fluid: is a completely different type of fluid. Manual transmission fluid job is to only lubricate manual transmission gears. Gear shifting is done manually and there is no pressure and very little heat inside a manual transmission.. Manual transmissions do not generate heat and manual transmission fluid does not lose lubricating properties for a very long time.)
Details from oil company Castrol regarding differences between Automatic and Manual transmission fluids.
What does “lifetime” Automatic Transmission fluid mean?
Well, no one really knows and they dont say. However, most likely means transmission fluid will not break down and transmission will work fine until your new car warranty expires.
Manufacturers refer to “lifetime” as lifespan of a transmission not lifespan of your car. Lifespan of a transmission for a manufacturer usually stops when warranty runs out, after that you are on your own.
When your transmission dies at 120k or 150k km: it can not be because of transmission fluid lost lubricating capabilities, transmission filter failed and/or contaminated transmission fluid clogged transmission lines. Nope, you will be told something else might have happened, maybe you don’t know how to drive, maybe was an act of God, maybe weather is too harsh, maybe…anything but fluid.
Test show synthetic transmission fluids will save their lubrication capabilities for a long time (not lifetime), but testing fluid lifespan in a laboratory environment and driving in real life are two completely different things.
Driving in low/high temperatures, stop and go traffic and short trips will oxidize transmission fluid. Also, additives added to transmission fluids will deplete over time. Depletion of these additives will reduce lubricating and cleaning capabilities.
Automatic transmission contains 500 to 700 parts depending on transmission type. Half of those parts are moving all the time under high pressures generating heat. Friction between these parts will produce lose metal and friction material particles from clutch plates. Fluid need to lubricate and clean these particles. Automatic transmission will fail when transmission fluid and filter are fully saturated by these particles.
Transmission Fluid Get Polluted Overtime
Oils (from olive oil to engine oil) will break down when used. Even more so inside a transmission with a bunch of plate clutches spinning at high speed and grinding at each other nonstop. That is why an automatic transmission has a filter and magnetic debris catchers inside, to remove contamination from transmission fluid.
Below is an image of used transmission fluid drained from a used car with only 64,000km on odometer. Notice color and compare it to fresh fluid on image above.
Example: a premium used car 6 years old with about 140,000km, went on limp mode and did not shift past its first two gears. On close examination was found that transmission fluid filter was clogged by debris.
Transmission fluid was never changed on this used car. Manufacturer recommended transmission fluid changes every 60,000km on maintenance booklet. After filter and transmission fluid change, car started shifting all gears. However, it never shifted normally again. Heat generated from driving in limp mode damaged transmission.
Automatic Transmission Oil Filter
Transmission fluids are getting better and can keep fluid lubricating properties longer. Transmission filters on the other hand are a different story.
Nowadays most new cars are coming off the line with “maintenance free” transmission filters integrated in transmission oil pans. These filters are not recommended as normal maintenance service by manufactures. However, as with anything else filters needs to be changed or will get clogged eventually.
How long a transmission filter last?
It depends on driving habits, weather and environment where your used car is operated. Toronto and other cities around the world can safely be considered a harsh environment. Harsh weather and bumper to bumper traffic.
Driving in traffic stop and go, especially at extreme heat or cold is hard on your transmission and your car in general. Cars usually go in limp mode because of transmission filters getting plugged. Plugged transmission filter will restrict transmission fluid flow and cause damage to transmission.
Automatic transmissions have very narrow passages where oil flows at high and low pressure. When these passages are blocked, damage will occur to a transmission.
How Often Should You Change Transmission Fluid
If you keep your cars only up to 100k km, automatic transmission fluid for you is lifetime. You don’t have to do anything, it will last with no problems that far.
If your plan is to keep a car as long as possible and want to extend operating life of your car’s transmission, then transmission fluid is not lifetime. Not even close.
Transmission fluid is very susceptible to heat. Heat over time kills transmission fluid and then dead transmission fluid kills your transmission.
Your aim should be having a lifetime transmission not lifetime transmission fluid. Automatic transmission fluid and filter (if equipped) should be considered a routine maintenance item and should be changed every 60,000 km or 3 years. This will ensure you get the most out of your transmission and your used car.
(If you are also looking for a fast and easy solution to sell your car, more here on “How To Sell Your Car Fast In Ontario” )
Comments: If you have any question related to this post or Used Car Toronto in general, don’t hesitate to use comment section below.
