[Indian2003]

Here is an interesting note about automatic transmissions and temperatures. There is a guy who repairs gearboxes down the road from my place. I might pop in tomorrow and visit him.
A few years ago he used to make torque converters which he delivered to shops in Norway and Sweden.

The original article is in Spanish and I had ask our friend Google for some help with a little input from me..

Automatic transmission

Most user manuals state that The automatic transmission is filled for life. Below we will give the reasons why ATF should be replaced on average every 40,000 km.

In an automatic transmission a lot of heat is generated due to the friction within the torque converter, when the clutch plates engage and that created in the gears and rotating guides. When this heat is produced, the ATF quickly warms up once the vehicle is in motion.

Under normal driving conditions the fluid temperature reaches 80 ° C (175 ° F), which is the average range in which the most liquids were designed to operate. If it is kept at that temperature the fluid can last up to 160,000 km and otherwise if the temperature rises (even under normal driving conditions it can pass) the life of the ATF is reduced causing the problems to start.

ATF oxidizes, changes color (brown) and produces an odor similar to burnt bread. While heat destroys the lubricating qualities and friction characteristics of the fluid, at the same time enamel begins to form on internal parts which interferes with the operation of the transmission.

If the fluid temperature exceeds 120 ° C (250 ° F) the rubber seals harden causing leakage and loss of pressure. Also at high temperatures the transmission begins to slip, which further aggravates the heating. Eventually the clutch burns out and the gearbox stops working. In the end, the only way to repair the damage is an overhaul, which comes at a considerable cost.

As a general rule, every 6 ° C (20 ° F) average increase in operating temperatures above 80 ° C will shorten life. of the transmission fluid to half. For example 91 ° C (195 ° F) the life of the fluid is reduced to 80,000 km. At 105 ° C (220 ° F) - it is the most common temperature in many transmissions - the ATF only works for 40,000 km and so on the protection mileage is reduced.

Do not risk suffering a mishap related to the transmission fluid automatic, make the change in the corresponding period and avoid paying more for not doing it.

[vigsom]

Originally Posted by sumannandy

The service center connected their mobile and read the error code as overheating transmission oil.

Thank You for this info, @sumannandy. Oils do lose their ability to retain their properties at higher temperatures. I'm throwing up another possibility on why the oil overheated - not enough cooling in the transmission oil cooler in the radiator. Maybe a radiator flush and a fresh coolant refill would also help in your case.

The coolant plays an important part in keeping the cooling/heat exchange system - jacket, water pump, radiator, transmission oil cooler in the radiator all functioning flawlessly over a long period of time. Toyota uses HOAT super long life coolant and recommends replacement of the coolant only at 1,60,000km and every 80,000km thereafter.

Originally Posted by Indian2003

Under normal driving conditions the fluid temperature reaches 80 ° C (175 ° F), If it is kept at that temperature the fluid can last up to 160,000 km

- As a general rule, every 6 ° C (20 ° F) average increase in operating temperatures above 80 ° C will shorten life. of the transmission fluid to half. For example 91 ° C (195 ° F) the life of the fluid is reduced to 80,000 km. At 105 ° C (220 ° F) - it is the most common temperature in many transmissions - the ATF only works for 40,000 km

Very valuable information Sir @Indian2003. Maybe this explains the guidelines set by Suzuki for automatic transmission fluid change interval under different driving conditions ( replacement at 1,65,000km under normal driving and 30,000km under severe driving). The ATF here is JWS3309 spec (Mobil ATF3309, Suzuki ATF3317) and one can extend this to Toyota T-IV too.

I've marked a red dot against ATF replacement recommendations in the following charts for quick reference.

Maintenance Schedule - Normal driving conditions


Maintenance Schedule - Severe driving conditions

[Artyom]

Is this inspection also applicable to Dual Clutch Transmissions (Hyundai DCT) to be specific? Also does the oil needs replacement irrespective of the running as in even if the running is less but the duration is more(Eg Vehicle is run 40k in 5 years). Does this also warrant an ATF replacement?

[GTO]

Thanks for sharing, Indian2003! Moving your post out to a new thread so as to warn others. A new thread means 100X the views & 100X the visibility in search engines, including Google.

@ BHPians, if you should spot any good post in an existing thread that deserves its own new thread, please report the post and we'll move it out for greater visibility.

Thank you!

Frankly, I never believe the "sealed for life" for any mechanical part. Different matter if its electronics, but mechanical + lubrications means periodic attention.

[ritedhawan]

One should keep track of the service maintenance schedule when it comes to replacing ATF. Please stick to the maintenance schedule when it comes to replacing ATF. I had a bad experience with our previous second-hand 2007 Honda Accord AT. I usually kept a track of engine oil levels, coolant levels, windscreen washer fluid levels but forget to keep a check on ATF. The result: one fine day driving down a highway the conventional AT gave up and when the vehicle was towed to our preferred mechanic he quickly identified lack of ATF level as the culprit. We had to dispose of the 2007 Honda Accord 2007.

Later I bought another second-hand 2008 Honda Accord AT and to this day I regularly check the ATF level along with engine oil, coolant level etc. The ATF can only be checked after running the engine for 10-15 minutes and then shut down the engine and wait for a few minutes to pop the hood and then check ATF to get the correct level of the fluid.

[ruzbehxyz]

A nice thread.

For the Ford Endeavour, the recommended transmission oil change is 2,50,000 kms or 10 years, whichever occurs first. Same applies to manual and Auto transmission and also to the oils of the differentials and transfer case in case of 4WD vehicles. However many owners have changed at 5 years interval citing our Indian conditions. This makes sense rightly so.

[vishy76]

Some extremely valuable info being shared here.

"Sealed for Life" is a term which is gaining popularity among many manufacturers these days, but I firmly believe it's just another by-product of engineering obsolescence. A fluid which lubricates parts and aids in heat transfer will wear out at some point or the other and need to be replenished. By the time the end user realises he should have changed it (typically occurs when most of the damage has been done to the GB), the life of the gearbox has already ended and there's no warranty to cover him either in most cases

The second point which I have often come across is to not flush or change the oil on a very old TC where the oil has never been changed before for very long. Just like an engine, sometimes the crud and the old oil deposits are what stops the torque converter from slipping and holds it together.

Flushing the GB and changing the oil too late could actually cause it to start slipping. Of course, if you haven't changed the oil on time and never will, there will be a point when the gearbox will fail completely (most probably the solenoids due to the bad ATF).

On this note, another idiocracy I am not in favour of is deleting dipsticks from transmissions. You either solely rely on how much you have taken out of the GB and put the same amount back in, or use scanners to determine levels.

[Aravind_M92]

ATF for DCT or AT or AMT is quite required given the state of moving parts. But for CVT, what is the required interval for CVTF change? My car is a Honda City, '16 make, has run about 60k kms. First change of CVTF was done at about 25k kms instead of the required 40k mark as mentioned by the book. Now my second change is being suggested at my current service.
I believe as CVT has lesser moving parts, fluid change frequency can be done as per the service booklet. I drive the car sedately. I barely rev beyond 4k. Is fluid change warranted at lesser frequencies?

[GrammarNazi]

Great thread!

At the same time I understand that apparently, if ATF hasn't been changed prudently and the gears start slipping, then it would be prudent to NOT change the ATF since the dense fluid would probably assisting in creating sufficient pressure to change the gears, and if you happen to change the ATF, this new fluid would likely cause gears to slip way more.

Toyota's Torque Converter ATs from AISIN as well as CVTs are engineered amazingly well & IMO over the years they've optimised the materials brilliantly to ensure longevity. I would consider them bullet-proof if ATF was changed when about 80% close to stated transmission warranty.

The metal drive belts in Honda & Toyota's CVTs are considered much better engineered than Nissan's CVT (sourced from JATCO). I would surely recommend Nissan CVT owners to change the ATF at around 70% of the stated ATF life or, if "sealed for life" the transmission warranty.

Correct me if I'm wrong/inaccurate, or would be best if someone can put it in clearer simple language !

[vishy76]

Originally Posted by GrammarNazi

Great thread!

At the same time I understand that apparently, if ATF hasn't been changed prudently and the gears start slipping, then it would be prudent to NOT change the ATF since the dense fluid would probably assisting in creating sufficient pressure to change the gears, and if you happen to change the ATF, this new fluid would likely cause gears to slip way more.

Toyota's Torque Converter ATs from AISIN as well as CVTs are engineered amazingly well & IMO over the years they've optimised the materials brilliantly to ensure longevity. I would consider them bullet-proof if ATF was changed when about 80% close to stated transmission warranty.

The metal drive belts in Honda & Toyota's CVTs are considered much better engineered than Nissan's CVT (sourced from JATCO). I would surely recommend Nissan CVT owners to change the ATF at around 70% of the stated ATF life or, if "sealed for life" the transmission warranty.

Correct me if I'm wrong/inaccurate, or would be best if someone can put it in clearer simple language !

You are spot on. AISIN is one of the most reputed names in the AT industry and is known to manufacture some of the most reliable TCs out there. Many manufacturers including MG and even VW have started sourcing from AISIN now.

JATCO on the other hand (which is a Nissan spinoff) was known to make weak CVTs that failed quite early. Their GBs are nothing to write home about.

[rayjaycleoful]

When should it be changed for the Hyundai Creta 6AT?
The manual states "sealed for life" I think. Would Hyundai ASS be equiped with knowledge/ tools to change this?

[Turbanator]

Originally Posted by Indian2003

Do not risk suffering a mishap related to the transmission fluid automatic, make the change in the corresponding period and avoid paying more for not doing it.

Originally Posted by ritedhawan

One should keep track of the service maintenance schedule when it comes to replacing ATF. Please stick to the maintenance schedule when it comes to replacing ATF. I had a bad experience with our previous second-hand 2007 Honda Accord AT.

I am a big follower of keeping original things, as those came from the factory for as long as possible

Instead of depending on some independent studies/ experiences, I will probably follow the manufacturers instruction and change the oils or any other component only if they have recommended.

We have many threads, I recollect for a Ford endeavour and a Honda where wrong oil change by the dealership has caused irreparable damage to the transmission. Most of the times, unless manufacturers instruct the dealership something in their manual or bulletin they may not be able to use the correct oil or follow the correct system on replacement. Even the quantities can be a question mark!

As an example, Toyota recommends, changing engine Oil every 5000 Km but oil filter only every 10,000 Km on LC-200. We know that if we are not changing the oil filter, lesser oil will be used but the workshop manual with the dealership mentions the exact same quantities at 5 K or 10K service. They refilled wrong quantities when I sent my LC for 5000 Km which I found out by checking dipstick and then back referred the owners manual which clearly mentions lower oil. But Toyota dealership will not do anything different unless their own workshop manual says otherwise. Since then, I always get the oil and oil filter changed. It does not cost too much and it’s not worth the efforts to reason every time.

Similarly, on my older LC, I decided to get the Air-suspension AHC oil changed at around 5 Years/ 80,000 Km ownership but the dealer had no clue. They did changed the oil but it took them 2 days to do it right way after taking help of someone from the Toyota as it wasn’t a normal. Toyota manual is silent on this if I recollect correctly but the Lexus- LX does mention the change.

[pram_ind]

Originally Posted by rayjaycleoful

When should it be changed for the Hyundai Creta 6AT?
The manual states "sealed for life" I think. Would Hyundai ASS be equipped with knowledge/ tools to change this?

ATF for my uncle's 2014 elantra was changed at 80,000 kms(5yrs). This was done at an FNG in Hyderabad. The liquid did not show any signs of burnt, as it was light brown colour, and per mechanic, it could run for another 20,000 kms.

There was negligible metal shillings in the bottom, which confirmed that there was no damage to gearbox.

By the way it was done as a preventive measure.

[SmartCat]

BRV's Owner Manual recommends CVT oil change at 40,000 kms or two years.

Here is the weird bit: Honda dealers don't know about it OR they tell you that CVT oil change needs to be done after 4 or 5 years. You have to insist on CVT oil change when you speak to the service advisor (who is always eager to push brake cleaning, door anti-rust treatment and what not)

[svmvale]

I agree, when there is a transmission, its always best to re-new the lubricant.

I read in this forum, VAG recommends change of transmission fluid every 1,20,000 kms on its DQ200 gear box.

As precaution, i got it done at 90,000 kms itself. My FNG said, max load on gear box comes while reversing while in full turn. He was able to feel the difference on my Vento.