How long does it take for a new oil to trash an old transmission?

J

Japanese

Joined
Dec 13, 2018
Messages
358
Location
Chicago, IL
Hi everyone,
I'm asking how long does it take for a new oil to trash a old transmission?
A friend of mine bought a used Lexus ES300 about 18 months ago. He replaced all the fluids although he knew that if the transmission oil wasn't regularly changed that may damage it.
A few months ago his transmission started to work rough and a month later the transmission failed. So this happened b/w 18-24 mnoths after he bought is and changed the ATF.

Did he damaged the transmission because he changed the oil or the tranny had already an existing issue? When you change the ATF on an old tranny does it break the transmission right away or may take a year or two as in this case?
Thank you.
 
If the new fluid was the proper fluid and the transmission was filled to the proper level, then no, the fluid change didn't cause the problem, it was already there. Automatic transmissions work great until the mechanical bits and clutch packs wear out. Changing the fluid properly doesn't cause this wear. Not changing the fluid could increase the rate at which it does wear though. How many miles were on this transmission?
 
Correct fluid is the key element, and the filter, and if overfilled or underfilled. Never heard of a tranny go bad a little bit after correct service. I have an 06' Camry. 120k . Bought private sale. Tranny fluid was toast. Took a lot of flushing to get that tranny clean. Lot of wasted tranny fluid to get the muck out. Shifted good prior, shifts 10X better now. There was an underlying problem, or the job was done incorrectly.
 
Anecdotally:
I once had an old tranny on a car flushed at a dealer .
This is a type of transmission that is usually reliable.

Fluid was real dirty. Car was 10 yrs old 86,000 miles (so likely all city)
Couple days later had missed shifts.

The valvebody had been ruined, I guess the pressure pushing dirt around intot he valve body did it and ruined it..
Should have done gentle pan drops and refills.

So it IS posisble to make things worse with a ill advised method.

Though I also still err on the side of immediate replacement when I buy a used car.
 
That's exactly what I did. After initial filter and gasket change, just unscrewed the drain plug. 5-6 qts at a time. Nice and easy. No problems.
 
New fluid has not ever and will not ever damage a transmission. That woukx be like saying oil changes damage engines. If done correctly it will never cause a problem at worst it will reveal a problem that was already there. Such as worn clutch packs that are only holding on because of the fluid being so dirty it is adding friction.
 
Japanese said:
Hi everyone,
I'm asking how long does it take for a new oil to trash a old transmission?
A friend of mine bought a used Lexus ES300 about 18 months ago. He replaced all the fluids although he knew that if the transmission oil wasn't regularly changed that may damage it.
A few months ago his transmission started to work rough and a month later the transmission failed. So this happened b/w 18-24 mnoths after he bought is and changed the ATF.

Did he damaged the transmission because he changed the oil or the tranny had already an existing issue? When you change the ATF on an old tranny does it break the transmission right away or may take a year or two as in this case?
Thank you.
Click to expand...
It was likely the pump. my Neon had the transmission pump fail with 153k miles. I changed the fluid per the manual.
 
Starving Electrician said:
New fluid has not ever and will not ever damage a transmission. That woukx be like saying oil changes damage engines. If done correctly it will never cause a problem at worst it will reveal a problem that was already there. Such as worn clutch packs that are only holding on because of the fluid being so dirty it is adding friction.
Click to expand...
An engineer friend told me that dirty transmission fluid actually decreases the friction at the clutches. The particulate acts as a solid lubricant. Fresh fluid will increase the friction at the clutches.

I think this is why resetting transmission adaptations after a fluid change is so important. The TCU needs to be able to re-learn the characteristics of the new fluid before potentially damaging the clutch packs.
 
YZJB said:
An engineer friend told me that dirty transmission fluid actually decreases the friction at the clutches. The particulate acts as a solid lubricant. Fresh fluid will increase the friction at the clutches.

I think this is why resetting transmission adaptations after a fluid change is so important. The TCU needs to be able to re-learn the characteristics of the new fluid before potentially damaging the clutch packs.
Click to expand...
That may be true doesn't quite make sense as clutch materials are chosen due to their high friction properties. Again though perhaps that is correct. I just can't wrap my head around how a thicker fluid that is loaded with grit would decrease friction.
 
Glenda W. said:
I simple drain and fill or fluid exchange will not damage a transmission. What is not recommended on a high mileage and neglected transmission is a power flush and or the use of solvents or additives.
Click to expand...
+1

Drain and fill with proper fluid won't hurt anything. A power flush can.. If it dies after a drain/fill it was already a dead man walking.
 
Everyone will have some opinions on this.

My running theory is that Neglected transmissions get "loaded up" with trans debris and depending how the fresh fluid is introduced can "stir up the pot" so to speak which sends the particles through the valvebody. This affects solenoid function till potentially the trans has issues. (Can load up the solenoid screens for example)

Most Japanese transmissions have a high micron strainer which doesn't really stop the debris from being ingested.

I've historically always installed Magnefine filters on all my auto cars and have always done trans services. I prefer drain and fills and or cooler line exchanges.
 
Starving Electrician said:
New fluid has not ever and will not ever damage a transmission. That woukx be like saying oil changes damage engines. If done correctly it will never cause a problem at worst it will reveal a problem that was already there. Such as worn clutch packs that are only holding on because of the fluid being so dirty it is adding friction.
Click to expand...
This. People have lots of imagination when it comes to this topic.
 
Japanese said:
Hi everyone,
I'm asking how long does it take for a new oil to trash a old transmission?
A friend of mine bought a used Lexus ES300 about 18 months ago. He replaced all the fluids although he knew that if the transmission oil wasn't regularly changed that may damage it.
A few months ago his transmission started to work rough and a month later the transmission failed. So this happened b/w 18-24 mnoths after he bought is and changed the ATF.

Did he damaged the transmission because he changed the oil or the tranny had already an existing issue? When you change the ATF on an old tranny does it break the transmission right away or may take a year or two as in this case?
Thank you.
Click to expand...
Perhaps you can peruse these existing discussions on this oft asked and popular question:

R

Thread 'Trans Fluid Change Myth/No Myth???'

Okay, so unfortunately I was raised believing the Transmission fluid change myth that if you haven't changed the fluid and you're past 100K then you are better off not changing it. I know I know you don't even have to say it, should have changed it earlier.
frown.gif


I'm new to the forum and have already learned a wealth of knowledge but I'm so torn up about this and I've read so many transmission threads my head is spinning. My truck has 135K on the original transmission fluid. It's been topped off before but never changed. So now I'm...
D

Thread 'Too Late/Unsafe To Change Tranny Fluid'

Looking for opinions to help in my situation.

I have a 1998 Nissan Altima, automatic transmission. The car has nearly 60,000 miles on it; I purchased used when the car had 25,000. A technician told me it probably wouldn't be safe to change the fluid on the car due to the mileage and the transmission fluid having never been changed. He said I should take it to a transmission shop and have them drop the pan/change filter (car doesn't have a fliter, only a screen).

I was wanting to do the drain/refill on my own, but I live in an apartment with strict rules, so I don't have to space or...
C

Thread 'ATF change question'

Is it real the myth about replacing the ATF after certain number of miles driven on the same fluid, will damage the transmission? I'm very much aware about many people saying it will hurt the transmission, but have you seen any case of a vehicle with a broken transmission caused but an ATF replacement?
BMW Dom

Thread 'Sign waiver for transmission fluid change?'

I took my car to a shop to get a quote on a transmission fluid and filter change. They were very nice, and had a clean shop.

When the tech drove my car and he said that he wouldn’t recommend a transmission fluid change due to the hard downshift. I wasn’t in the car with him.

They said I would need to sign a waiver that if the transmission breaks after they change the fluid, they wouldn’t be responsible.

2009 BMW 328, 127k miles.

Should I sign the waiver, or take it somewhere else?
  • Like
K

Thread 'ATF change in high mileage vehicles inquiry'

Hi everyone,

I work for a small but fast growing company that provides convenient maintenance service to privately owned vehicles. Something like Meineke or EZ Lube, but we are not a franchise.

I know this is an old topic, but my searches didn’t yield the answers I need.

As you know, most people have to keep their vehicles for a longer time than they used to. They have also become more concerned about the correct maintenance of their older cars.

Because of this situation, it is very important to separate myth from fact about the possibility of automatic transmission failure if the ATF...
E

Thread 'Changing ATF in an old car'

What are your thoughts on changing the Automatic Transmission Fluid on a 33 year old car that has the original Fluid and 50,000 miles.Fluid is Red and appears clean.I have heard a suggestion of draining out and replacing a litre of fluid every few thousand miles,instead of replacing the entire amount at one change,what is the reasoning behind this idea? is there any merit to this,or is it nonsense? Would you just replace all the Fluid,and fit a new strainer/filter in a single drain and refill,and maintain from there?
J

Thread 'Changing ATF kills old transmissions???'

I had a guy who works for a transmission shop tell me that an old transmission that might be on its last leg is more likely to go ahead and expire soon after an ATF fluid change.

What do you guys think?
T

Thread 'Changing Trans Fluid Bad Idea?'

I just bought 12 quarts of Honda ATF so that I can drain & refill the auto transmission fluid on an '04 Pilot at about every other oil change.

I was surfing the net, and I found a Pat Goss (celebrity mechanic) column from the November 2003 Washington Post where a reader asked why more do-it-yourselfers don't change their ATF.

Goss responded by saying that most people don't own a several thousand dollar fluid exchanger and that merely dropping the pan (the Pilot doesn't have a pan) and replacing about 1/4 of the total fluid may actually be detrimental - not beneficial - for the...
P

Thread 'First Transmission Fluid Change at High Mileage (100,000+)?'

My son's 2010 Toyota Corolla has 100,000 miles on it. Transmission fluid never changed. Friends 2009 Venza; same thing.

I have seen several options discussed:
1. Only do one drain and fill.
2. Do several drain and fills.
3. Drain, fill. Then unhook transmission line and let transmission pump fluid out, replacing one quart at every quart pumped out. Do this until fluid runs clean (this is what I typically do).
4. Do transmission flush with flush machine. No one seems to recommend this out of concern that deposits will be broken loose and cause damage.
5. Do nothing. Because the...
C

Thread 'when/if to change trans fluid? miles or years?'

I have to be honest, prior to reading on this board i'd generally not even been aware that transmission fluid in an automatic would need changing... but then thats a habit inhereted from a father and cars didn't last as long in his day. So just like this site has opened my eyes about synthetics and better coolants and stuff, what is the distilled wisdom of changing transmission fluid in vehicles where it WASNT mentioned in the manual or even something to be aware of at the time? I'm wondering if all those things I heard about engine oil, especially 'clouding points' in cold climates and...
G

Thread 'Why do transmissions fail after changing the fluid?'

I got and email from a friend who didn't make it back from his trip.

He had is transmission serviced, then hooked up the 16' fishing boat and headed up north in a Bravada with 90k miles.

On the way back he smelled something burning and noticed the tach was at 4k instead of 2k. You know the rest of the story, they put his SUV on a flat bed and towed the boat behind the truck all the way back home.

Does it seem that transmissons seem to go more often ofter you change out the fluid?
8

Thread 'is it a bad idea to change REALLY bad tranny fluid?'

Group,

In searching through the archives, i haven't seen much on this topic. i have heard from some people that if the fluid is pretty dark/burned, you will do more damage flushing the transmission fluid than if you just leave it alone.

is this true? what is the reason? what exactly will happen if you change really bad fluid and what causes the transmission to need an overhaul soon after? lastly, how would you determine the fluid is beyond service. obviously you should have changed it as needed but we are assuming you didn't.

This has nothing to do with one of my cars, but is a question...
F

Thread 'Transmission Problems....Need Opinions'

My son bought a 2000 Ford Explorer with 88K miles on it from a guy who said the transmission was going bad and slipping. It was about a quart low, we added fluid and he has drove it for a couple of days and so far it seems to be okay. The fluid is pretty dirty and we were going to change the filter and add new fluid.

Some have said not to change the fluid if you think the transmission is going bad, the dirt and grit in the fluid is keeping the transmission working.........new fluid may make it slip worse.

I say put in a new filter and fluid and see what happens.........what's the opinion??
M

Thread 'Myth about changing old ATF'

Hey I know this is probably a topic that has been discussed but just wanted to cut to the chase instead of reading through a bunch of posts. I recently bought an '87 Cherokee, with 160,000 on it. Runs and drives good, no slipage or any other problems, but the fluid is dark, does not smell burned at all, just looks dirty, almost brown. I don't know if it's original or just old and am not sure if I should change it, so just looking for some opinions or advice or experiences if anybody knows this particluar transmission, not sure which transmission, but it's the 4.0L straight 6 engine. The...
S

Thread 'Volvo dealer cautions against ATF change. Ever.'

My son just bought a used 2018 Volvo S60 Cross Country with 22,000 miles. It has the 8 speed automatic, Aisin, I believe. I stopped by the dealer to get quotes for replacing ATF, transfer case fluid and differential fluid. Two service guys and one mechanic strongly cautioned me not to change the fluid. Ever. Something about the transmission adjusting to the changing viscosity of the fluid...

This sounds like absolute nonsense to me, but they were adamant on this, saying they've seen too many problems caused by changing the fluid.

I'm thinking about doing drain / fills at around 50 or 60k...
S

Thread 'Change-Flush transmission fluid at 120k'

2011 Toyota camry V6 with 120,000
hot climate
Would you change or flush the transmission fluid
(A car fax doesn’t show that it’s ever been done)

Thanks
 
Japanese said:
Hi everyone,
I'm asking how long does it take for a new oil to trash a old transmission?
A friend of mine bought a used Lexus ES300 about 18 months ago. He replaced all the fluids although he knew that if the transmission oil wasn't regularly changed that may damage it.
A few months ago his transmission started to work rough and a month later the transmission failed. So this happened b/w 18-24 mnoths after he bought is and changed the ATF.

Did he damaged the transmission because he changed the oil or the tranny had already an existing issue? When you change the ATF on an old tranny does it break the transmission right away or may take a year or two as in this case?
Thank you.
Click to expand...

if the new fluid dislodges accumulated dirt, it happens quickly, not 18 months after changing. within days usually.
 
New oil doesn’t trash a transmission.

Neglect trashes transmissions.

Every perceived negative, dislodging dirt, whatever, listed is the result of having a neglected transmission.

If the transmission lasted 18-24 more months after new fluid, it was not the fluid that did it in - it was the lack of prior maintenance.
 
Japanese said:
Hi everyone,
I'm asking how long does it take for a new oil to trash a old transmission?
A friend of mine bought a used Lexus ES300 about 18 months ago. He replaced all the fluids although he knew that if the transmission oil wasn't regularly changed that may damage it.
A few months ago his transmission started to work rough and a month later the transmission failed. So this happened b/w 18-24 mnoths after he bought is and changed the ATF.

Did he damaged the transmission because he changed the oil or the tranny had already an existing issue? When you change the ATF on an old tranny does it break the transmission right away or may take a year or two as in this case?
Thank you.
Click to expand...
That transmission had one foot out the door when he got it.
 
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