Transmission Fluid

Idk about that problem but what I normally do is lift up the truck and wait for the truck to be cold in the morning. Drain and measure the fluid that came out and fill in the same amount in with new fluid.

 

Change it if it makes you feel better, but I'm still waiting for some documentation that shows changing the fluid prolongs transmission life. I started driving in 1973 and have never changed the fluid on any vehicle I've ever owned. I've got over 1/2 million combined miles sitting in my driveway with the factory fluid in the transmissions. If the transmission dies in one of them today, I'll replace it with a new transmission and be way ahead financially because of the money I didn't spend over the last 50 years changing fluid every few months.

Here is the issue with changing the fluid in an older, high mileage vehicle. If your transmission is still sound internally changing it won't hurt a thing. I don't think it helps anything either, but it certainly doesn't hurt.

BUT.... if the transmission is in decline keeping the old fluid in there buys you time. You might get another few years out of it before it finally dies. That dirty, nasty looking old fluid is what is keeping your transmission from slipping. New fluid is actually too slippery, and your transmission will start slipping shortly after you change it.

This is why any reputable shop won't touch a high mileage transmission. The only way to know if the transmission is in decline is to take it apart. It just isn't worth the risk. They don't want angry customers coming back 2 days after the transmission service with a dead transmission.

 

thanks for all the help !!! I'm gonna stick with it , since it has 197000 , I'll do it again in near future. I'm interested in a cooler now , but don't tow.

 

Does the cooler actually cool the fluid if you are stationary? Don’t know why it would take longer to get to temp while it’s parked.

 

I thought I was good a math but I can’t follow your point. You say you are WAY ahead by NOT changing the fluid over the course of 500k miles. If I performed a drain and refill every 30k miles at 4 quarts that’s about $50 every 30,000 miles. 500,000 miles divided by 30k change intervals is 17 changes x $50/change is $850. Where can you get a new tranny for $850?

 

I had the exact cooler you have installed on three of my cars over the years and never had indications or symptoms that the fluid was too cold, except maybe for the first 5 minutes of driving on a winter morning when it was 10 degrees F or lower out. Th cooler was installed downstream from the in-tank radiator cooler (trans fluid outlet). Within a few minutes the coolant was warming up the fluid on its way through. The coldest I ever drove in was up in Maine one year when it dropped to -26F . I let it sit for a minute or so. It shifted slower into drive and changed gears a little slower, that was it. With the exception of maybe someone who lives in the far north near the arctic circle, I really don't subscribe to the idea that you can over-cool automatic transmission fluid. (YMMV)

 

The simple truth is that the chemicals that make up transmission fluid aren't magic. Fluid shear, contaminants, acidification, oxidation, moisture, heat, thermal cycling, etc. all work to break down the chemical compounds in transmission fluid. The question is: how far can you go without changing it before that break down becomes significant enough that it's no longer doing it's job or is causing excessive wear to the components in your transmission?

It's not like it's a one day it's good then you reach a point and it's bad—the breakdown starts as soon as your pour it in your transmission. And at some point, it's no longer going to be within spec, or in other words, no longer in a condition to satisfactorily to operate the transmission or protect the components that make up the transmission. Additionally, contrary to your point, old fluid tends to be more "slippery" than new fluid because of that same fluid breakdown. If the friction modifying chemicals, detergents, base fluid stock, etc. breakdown, the fluid isn't going to be able to maintain it's physical properties (including how "slippery" it is, or rather it's viscosity and adhesion/cohesion characteristics) well enough to do it's job. Not to mention that contamination in the form of the presence of solids or moisture ingress tend to make the these types of fluids more "slippery". The "if it's never been changed before and your car is high mileage, don't change it" shtick is an old wives tale IMO.

Mileage may vary of course—depending on your climate, driving style, where you drive, etc., you may sell or trash any given vehicle before the transmission fails due to poor fluid condition. But the fact of the matter is, at a certain point, you're operating your transmission on "worn" fluid and that fluid won't operate or protect as well as new fluid. Could it be fine? Sure, it could be. Hell, I'm sure we've all seen YouTube videos of BMWs with 40k miles since their last oil change—the engine is trashed, but it still ran. That same goes for your transmission and the ATF you put in it.

All that being said, in my opinion when a component on one of my vehicles is breaking down, including fluids, I change it. I believe in preventative maintenance—and in this case, I go (roughly) by the manufacturers recommendation: 60k miles.

Here are some SAE articles that discuss fluid breakdown and their effects, as well as a brief series of white papers published by Allison Transmissions and GM on the subject. For the papers published by SAE have to pay to read the full article, but the abstracts should give you a good idea of the content of the studies and their conclusions. Note, that not all of them are talking directly about what we are talking about here, some older, some newer, but they should help give some broad information on the subject (and this was literally just the on first page of Google search results I found; I'm sure you could find even more applicable papers if you searched further).

Allison/GM white papers:
https://www.lube-media.com/wp-conte...LUIDRESPONDSTODAILYOPERATIONSPart1of3etal.pdf
https://www.lube-media.com/wp-conte...LUIDRESPONDSTODAILYOPERATIONSPart3of3etal.pdf
https://www.lube-media.com/wp-conte...IONFLUIDRESPONDSTODAILYOPERATIONSPart3of3.pdf

SAE papers:
https://www.sae.org/publications/technical-papers/content/2001-01-0867/
https://www.sae.org/publications/technical-papers/content/2008-01-2395/
https://www.sae.org/publications/technical-papers/content/660097/


Also, your math seems a bit off—because who the hell is changing their transmission fluid "every few months"? I don't think anyone is advocating for that. If we go by Toyota's recommendation of 60k miles, and assume we buy 15qts of Toyota WS (included some extra to be conservative/account for spillage), if you did the change yourself and we took ONE Tacoma to half a million miles, which is not the case for most owners, your cost is still going to be less.

Going by Toyota's maintenance interval, that's 8 fluid changes. You can buy a quart of WS for ~$15, bringing us to $225 per change, and a total of $1800 for all 8 changes. A brand new automatic transmission from Toyota is ~$2700-$5300 depending on the year and specific Tacoma model. So even in this extreme case, your math just doesn't work out.

At the end of the day, its your truck, you do you, but it's cheap preventative maintenance to ensure you get the most out of your transmission.

 

Yeah I don't buy anything he says.

 

Yes it runs cooler just sitting there in park, the 699 is huge compared to the oe cooler so just the fan drawing air across the aprox 3x amount of surface area might be why.

 

Just a quick comment on your setup, you may want to adjust the orientation of your cooler. With how you have it oriented currently, ATF may not be reaching the upper parts of the cooler. Still better than the stock cooler though.

 

Well I spent half the day trying to figure out how to orient cooler up or horizontal . Nothing I was happy with so I kept it like this . I don’t like the idea of air pockets , seems 50/50 on whether it will be inefficient. As long as it’s not worse , opinions?

 

I mounted mine with the inlet at the bottom and the outlet at the top. In this orientation the cooler will fill from the bottom up before reaching the outlet, maximizing the amount of fluid in the cooler while also allowing it to drain completely when the engine is off (similar to the stock cooler). Here are some pics of my set-up when I did it:
https://www.tacomaworld.com/threads...en-tacoma-today.6499/page-11432#post-26849022

I just grabbed some angle aluminum and cut some pieces to fab up the mounts. I bolted it all together with stainless fasteners and a combination of stainless washers and neoprene washers to help damp vibration. I drilled a single hole to attach the bottom mount to the truck, but all of the other attachment points use existing holes on the truck.

Let me know if you want more pictures and I can go snap a few.

ATF is relatively viscous, so you may be getting a good percentage of the cooler filled while the engine is running, but it does leave room for air pockets, especially considering that air is less dense at the ATF and has nowhere to go if it gets trapped up at the top of the cooler.

 

I couldn’t agree more. I’ve been driving since 1978, have had more vehicles than I can count, and have never ever changed transmission fluid on any of them. That said knock on wood, I’ve never owned a vehicle that had any transmission problems. I run them well over 200,000 miles before I get rid of them… just my .02

 

Yeah I tried to turn it to be like yours or barbs up but cooler is so big i couldn’t find a spot I liked due to not wanting to kink hoses on the side you put yours on . And not fitting well on pass side . I may go to a hd cooler so i can use an 90 deg fittings to achieve a side exit like yours . I’ll figure it out.

 

I ran into the same issue; ended up running some extra hose to run a "strain relief" loop so that it wasn't making any hard turns that might kink the hose.

I plan on finding some pre-molded tube or maybe an intermediate angled fitting to clean it up at some point, but it's worked fine so far and I've been lazy hah.

 

I believe you’ll need an OBD reader to check the temp that way, but here’s a link that gets a bit more specific about the years without the required pin for jumping. Starts around post 8.

https://www.tacomaworld.com/threads/transmission-fluid-mistake.737117/

 

gearcruncher knows best, i use max life valvoline atf its full sythetic