High Mileage AT Fluid Swap, Yes or No?!

Speaking of high mileage fluid swaps...

What is the consensus on TW regarding changing your high mileage AT fluid if it has never been done before?

I've never changed the tranny fluid on my 2013 and she now has 205,000 miles on her. I just recently started towing a travel trailer and now something I've never given an ounce of thought to doing is suddenly nagging at the back of my mind.

Rumor has it this is a bad idea and may cause slipping/failure, is this just BS or is there any truth to it?

I'm inclined to change the fluid because "better late than never".

To be clear, I'm having no issues whatsoever with the transmission at this time (or before).

 

Drain the pan, drop the pan, clean the magnets, replace the filter, then follow the DIY full transmission flush and you will be good.

 

I can dig it. Thanks for the quick response.

 

@gearcruncher Might be able to add some more insight, but id imagine he'd agree to what i mentioned above or additional things to do.

 

If you are 100% concerned. Capture and save the AFT in a clean container.

if you have slippage or other issues drain the new and use the old stuff you saved

let us know how it goes. Many others will have the same concerns. I think mine was done at 120k w no issues. FSM called for 100k flush I believe.

 

I agree 100 %
The key to a successful high mileage transmission service is removing the pan to remove the junk in the pan . A lot of guys just remove the drain bolt on the pan rather than dropping the pan and fill the pan back up . This can be troublesome as the super detergents in the new fluid can lift contamination from the magnets and pan and displace those contaminants into the all aluminum valve body
https://www.tacomaworld.com/threads...e-2nd-gen-transmission-pan-and-filter.726329/

 

Awesome, Thanks!

 

Drive it.

There are plenty vehicles on the road with 300,000- 400,000 miles on the factory fluid. At this point changing it won't help anything. Either the fluid and transmission is still good, or the fluid is bad and the transmission is compromised. I've never seen any proof that changing AT fluid extends the life of the transmission. Some guys change the fluid every 50,000 miles and still have them die under 200,000. Others drive them 400,000 miles and never change it. Some guys literally spend more money servicing their transmission than it will cost to replace it. And all of the evidence says it will have to be replaced at about the same point either way.

If everything is still good changing the fluid at this point won't help or hurt. But if the transmission is already compromised keeping the old fluid in there will buy you time. Chances are good it will continue to work for a year or more. But if you have a compromised transmission changing the fluid at this point will result in complete failure within a few hundred miles.

FWIW, I have 219,000 miles on my 2007 and have no plans to change the fluid. The guy who runs our local transmission shop has 300,000+ on his 3/4 ton Chevy that he regularly tows 10,000 lbs. He has never had the pan off his transmission. I have almost 1/2 million combined miles on vehicles in the driveway. All of them have the factory fluid in the transmissions. I've been driving since 1974, never changed the transmission fluid on any vehicle I've ever owned. Never had an issue.

 

Stuff like this makes me question everything

 

Hahahaha, You are winning my friend!

 

Honestly this is about how I operate...if it aint broke don't fix it...

 

There is a reason Toyota changed their transmission service interval from 100k as it is listed in your owners manual down to 60K .
The engineers who designed the 5 speed Aisn -Seiki transmission prefer the fluid be changed every 30 K
The transmissions in newer cars and trucks have adaptive learning and compensate for wear in the transmission by increasing pressures and modifying clutch volumes . In an effort to avoid premature wear from higher heating cycles of the fluid ,Keeping the depleted reagents fresh is a critical part of the service interval considering this transmission is a solid block of aluminum including the valve body .
Particulates in the fluid can kill this transmission quickly . Any steel floating in the fluid acts like sand paper in the valve bodies .
Gone are the days of the indestructible cast iron valve bodies .

 

Oh yeah I get it (even though it doesn't seem like it since I've never changed my AT oil). I will be changing the fluid for sure. I was being flippant with my earlier remark about it not being broke.

 

I changed mine twice (at about 75k and 150k) and never had any issues.

 

I did mine at 150k and it made a pretty big difference. I bought the truck used with like 148k and I don’t think the transmission fluid had ever been changed. The first time driving it after I replaced the fluid, it really felt like a new truck!

 

Wow, did you just notice it in the shifting?

 

Shifting is way better than before. Probably the biggest thing of course. But it also runs and even idles better.

 

i did the drain and fill somewhere near 250,000 mi
either way you go, try getting it into the temperature check mode correctly...
before, just to verify...

 

Very cool. Trucks like a little TLC, just like people

 

Schrödinger's Transmission - It is both Good and Bad until you drop the pan, change the fluid, and find out what happens. My Tacoma has over 250,000 miles on it and has never had the Transmission fluid changed. No issues. There are a few Toyota Master Mechanics on YT that say "If your high mileage vehicle has never had the transmission fluid changed, DON'T CHANGE IT NOW!"