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

[50yr Street Mech]

This myth of changing fluid on a high mileage transmission is an " old wives tale". I do agree with not using the power flush method though. Forces dirty fluid out, and into valve body. Gentle spills and fills until you get it clean. If filter is accessible, change it with a quality filter. Some are not, and you have to split the engine from tranny ( like my 13' Pilot ).

 

[Japanese]

How many miles were on this transmission?

The car had 160K miles on it. Highly suspicious though because it was 2001.
He changed the ATF and after 20K miles the transmission failed.

 

[Japanese]

Was the proper OEM fluid used? Not talking about "equivalent" fluid based on spec, I'm talking exact OEM fluid?

I don't know, but assuming - not, because it was not done at a dealership.

 

[Japanese]

Thanks everyone for the information.
Just wanted to clear it a bit more for myself too because i think I was one of the people that told hin to change the ATF but on his own risk.
However, the tranny was already trashed and the mileage of the car might be tempered too.

 

[MaximumMini]

I would have to agree with the consensus. Fluid change didn't cause the failure unless wrong fluid used.

1999 Dodge Grand Caravan, bought with 155k miles.
Changed ATF+4 and filter within days of purchase
That was in 2008ish.
Changed ATF+4 and filter again in 2015.
Never a problem. Still going strong today. (knock on wood).

 

[kschachn]

I don't know, but assuming - not, because it was not done at a dealership.

No reputable fluid that lists a specification or approval as “recommended” or suitable is going to wreck a transmission in 20K. It may change the feel or shifting quality but it’s not going to cause that type of failure.

On an Asian vehicle like this the only fluid that actually has the Lexus or Toyota approval or specification is the OEM branded fluid. Asian manufacturers do not license their specifications. Therefore any fluid used that’s not branded OEM is always a recommended fluid. Even dealers don’t use that fluid unless you pay extra for it.

 

[50yr Street Mech]

That's the mistake I made on my 13' CRV. Did a spill & fill using Idemitsu fluid. Fluid said it was compatible to OEM Honda fluid. Guess what, 1 week later I had 2 gears left. 1st & reverse. Very costly mistake that was. Put back a Honda re-man with a 3yr/36k warranty. All future spill and fills with Honda OEM fluid. 300K later no problems.

 

[JDenyer232]

The car had 160K miles on it. Highly suspicious though because it was 2001.
He changed the ATF and after 20K miles the transmission failed.

Thats like 7000 miles per year. Most likely the car was a city car or short tripper. Stop and go driving equals lots of shifts, the more shifts the more things wear.

 

[50yr Street Mech]

Correct...All my cars are short trippers, which is why I installed Magnefine inline filters on all of them. Catch more of the wear and tear material. Won't stop the wear and tear though

 

[kschachn]

That's the mistake I made on my 13' CRV. Did a spill & fill using Idemitsu fluid. Fluid said it was compatible to OEM Honda fluid. Guess what, 1 week later I had 2 gears left. 1st & reverse. Very costly mistake that was. Put back a Honda re-man with a 3yr/36k warranty. All future spill and fills with Honda OEM fluid. 300K later no problems.

So you're saying that one spill and fill with the Idemitsu recommended fluid killed your transmission in one week?

 

[50yr Street Mech]

Correct. Just one spill and fill. The Critic was kind enough to post some information regarding this. There are additives in the OEM fluid. The Idemitsu did not have these additives. It would work in a Toyota, not a Honda. Toyota tranny's are less picky ....Thank you Critic....Yet the fluid said it WAS compatible with Honda OEM. Well, my tranny didn't like it.

 

[kschachn]

Correct. Just one spill and fill. The Critic was kind enough to post some information regarding this. There are additives in the OEM fluid. The Idemitsu did not have these additives. It would work in a Toyota, not a Honda. Toyota tranny's are less picky ....Thank you Critic....Yet the fluid said it WAS compatible with Honda OEM. Well, my tranny didn't like it.

Oh, it didn’t just “not like it”, it rendered it inoperative.

Which additives are these that are so critical they are the thin line between everything being okay and mechanical failure in one week?

There must have been absolute heck wreaked on the world from that fluid. Class action lawsuits and the whole works. Did you get a lawyer involved? Or contact Idemitsu to file a claim? Imagine people who replaced all the fluid with this recommended product, they must have had instant failure.

I wonder how bad the rest of the recommendations are that Idemitsu makes for their other fluids?

 

[50yr Street Mech]

I don't have the specs on it. The Critic had that info. Whatever, that was a long time ago, and I learned my lesson. Always did spill and fills on that tranny with OEM Honda fluid every 15k. This ONE time I used Idemitsu, and that was the end of it. Wanted to save a few bucks on the fluid. Didn't quite work out that way. I'm very happy with the Honda re-man unit. Still going strong after 300K. Got my money's worth out of that tranny

 

[clinebarger]

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.

Guessing this was a U140E? If so those are pretty failure prone compared to other Aisin-Warner units like the tank of a 4 speed.....The A541E used in the 1MZ-FE Avalon & Camry.

 

[ryanschillinger]

I’ve changed trans fluid in neglected vehicles without issue but if the fluid was chunky and burnt I wouldn’t touch it and would expect a trans replacement.