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yes, but the lock-up only happens in last gear, right?....and when accelerating from first to last ,its not locked up i don't think, so any reduction in slippage would help..
 

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yes, but the lock-up only happens in last gear, right?....and when accelerating from first to last ,its not locked up i don't think, so any reduction in slippage would help..
Most modern automatics will lock up in most gears at a steady speed. Generally only first or first and second gear are exempt from lockup on modern transmissions. I'm not sure about the specific setup for these but converter slip is still unlikely to be a big culprit here.
 

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My local Volvo dealer in San Antonio recommends the fluid to be changed every 50k miles (as mentioned by another poster). They charge right around $300 for it. There is an independent Euro mechanic that does everything from German to Swedish to Italian here in San Antonio and he recommends the fluid change as well and doesn't believe in lifetime fluids. I don't believe lifetime fluids either, just think about the amount of heat cycles, wear of the components that's trapped by the fluid, etc. All these longer intervals of fluids, etc. started when free service was offered during the car's warranty period which most of the time matches the most popular lease periods. The car is taken care of while leased after that it's someone else's problem to take care of. Works well for people changing cars every couple of years but if you like to keep your cars around, change the fluid.
 

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every little bit helps...less converter slip + less internal friction + less clutch pack slippage = 1.5 mpg gain...
Less converter slip would require thicker, more viscous fluid. Less internal friction would require thinner, less viscous fluid. The new fluid cannot be both more and less viscous at the same time.

The clutch packs should not slip at all (save for a few milliseconds during the instant the gears change) and would not have any significant effect. If a clutch pack is slipping enough to affect mileage, the car needs a transmission rebuild and changing fluid cannot save it.

Mileage gains from fresh fluid are likely the result of lower internal friction and nothing else. Converter slip and clutch pack slip are simply not going to be measurable factors given how a modern automatic transmission works.
 

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Less converter slip would require thicker, more viscous fluid. Less internal friction would require thinner, less viscous fluid. The new fluid cannot be both more and less viscous at the same time.

The clutch packs should not slip at all (save for a few milliseconds during the instant the gears change) and would not have any significant effect. If a clutch pack is slipping enough to affect mileage, the car needs a transmission rebuild and changing fluid cannot save it.

Mileage gains from fresh fluid are likely the result of lower internal friction and nothing else. Converter slip and clutch pack slip are simply not going to be measurable factors given how a modern automatic transmission works.
im not gonna sit here and argue with you, cause that's what you like to do on here.....we're talking NEW fluid as compared to OLD fluid, get it?....and we are talking milliseconds as to making a difference...ok?
and if you look at my first post , i didn't adamantly state anything as a know it all fact, just conversation...
christ....
 

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furthermore, NEW fluid can maintain its viscosity ...AND... provide better lubricity as it's additives are not used up, or, contaminated.....best of both worlds.....
 

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Less converter slip would require thicker, more viscous fluid. Less internal friction would require thinner, less viscous fluid. The new fluid cannot be both more and less viscous at the same time.

The clutch packs should not slip at all (save for a few milliseconds during the instant the gears change) and would not have any significant effect. If a clutch pack is slipping enough to affect mileage, the car needs a transmission rebuild and changing fluid cannot save it.

Mileage gains from fresh fluid are likely the result of lower internal friction and nothing else. Converter slip and clutch pack slip are simply not going to be measurable factors given how a modern automatic transmission works.
im not gonna sit here and argue with you, cause that's what you like to do on here.....we're talking NEW fluid as compared to OLD fluid, get it?....and we are talking milliseconds as to making a difference...ok?
and if you look at my first post , i didn't adamantly state anything as a know it all fact, just conversation...
christ....
I know you didn't. I'm just trying to point out how a transmission works and why the theories you've posited don't all pan out. Explaining how things work and why a theory has shortcomings isn't arguing, it's providing clarification and edification. I know you didn't post anything adamantly as fact, that's why I simply pointed out which of your theories could be true and which couldn't. If you were truly interested in conversation and information exchange that information should be of interest.

Yes, we're talking about old fluid vs new fluid. To cause increased torque converter slip, old fluid would have to be less viscous than new fluid. To cause increased friction in the transmission, old fluid would have to be more viscous than new fluid. Old fluid cannot be simultaneously both more and less viscous than new fluid, so the benefit of new fluid on fuel mileage has to come either from reduced torque converter slip or from reduced internal friction, but not from both. Because the effects of torque converter slip are mitigated by the fact that the lockup clutch engages in 3rd, 4th, 5th, and 6th gears and at speeds as low as 25 mph (based on the specs I've been able to find), and because the increased clutch pack dust that accumulates in old fluid will act as a viscosity increasing agent, the increase in fuel mileage is going to come from the superior lubricity and reduced viscosity of new fluid. This means that it's due to the reduction of internal friction.

As for clutch pack slippage, there's simply no way that a few milliseconds difference during a gear's engagement isn't going to be able to affect mileage. There's simply not enough time for it to affect things. If a clutch pack were slipping enough to affect mileage it would be incredibly noticable and would feel like a slipping manual transmission clutch; drivability would be awful and you'd need a transmission rebuild to fix it.

The intent here is to provide information for people who want to know how this works and what the mechanism is for why a change of transmission fluid might improve mileage. Theories are great and I love that people are thinking about the why and how, but it's not an insult when someone explains why one theory or another doesn't work or isn't plausible.
 

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Theories are great and I love that people are thinking about the why and how, but it's not an insult when someone explains why one theory or another doesn't work or isn't plausible.
Well stated :thumbup:

I, personally, enjoy reading your posts :beer:
 

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Well, there's a third part to this that kicks out technical analysis on your part and the original, anecdotal statement of mileage increase and analysis of my part.
Gas mileage is a huge factor in automobile manufacturing and they spend large amounts of time and money searching for the smallest increment of mpg increases. They examine everything, including transmissions. ( oh yeah,and piston rings) That's why we have 6,7,8 speed, cvt trannys. (and t5 engines that use oil). In no official, scientific, engineering, or expert report is there ANY mention of old vs new fluid as to mileage improvement from trannys. None. Yes, experimental analysis on their part has led to viscosity as a factor...and improvement therein, but not concerning old or new.
That's probably one reason why dealers and associated manufacturers can get away with " lifetime" fluid. It doesn't affect mileage, according to " experts"...( that's a guess, i'm no " expert")
....so, according to these experts who know transmissions more than you or me, old or new fluid is irrelevant to mileage.....or they're not as smart as they think they are.....( i wonder, maybe we're on to something here ?)
.....yet, hmmm...mileage increases are reported. So that leaves us..where? You're an expert, telling me my analysis is flawed, yet , experts higher than you could care less as to whether fluid is old or new. That leaves your analysis (from their point of view) as irrelevant, unscientific, and flawed. It puts me in the same boat. And mileage increases due to fluid changes, therefore, are just imagined or, of course, not measured accurately and precisely.
I say, these experts are wrong. Experts can be wrong.
so i'll stick with my statement, new fluid increases the efficiency of the converter, reduces mechanical friction, and helps with clutch pack slippage, no matter how minute.
....or, (i don't know) Maybe i should just jump on the real experts' bandwagons and say it doesn't matter one way or the other.
 

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so, according to these experts who know transmissions more than you or me, old or new fluid is irrelevant to mileage.....
No. That is not what they're saying when they say it's a lifetime fluid. All they're saying is that it should be sufficient to avoid mechanical issues for an acceptable percentage of use cases for the expected service life of the vehicle. It says nothing about expected fuel mileage over that period.

Fuel mileage tests are done with new vehicles. The manufacturer doesn't care what the fuel mileage is at 50,000 miles because the testing takes place on new vehicles, not old ones. There's no guarantee from the manufacturer that a car will get rated fuel mileage even just out of the showroom, let alone 50,000 miles (or even 10,000 miles) later. If old fluid causes a decline in mileage at 50,000 miles or more, the manufacturer doesn't care as long as reliability isn't impaired. They'll happily spec the fluid as "lifetime" despite the mileage drop off because they can get the good "official" mileage when they test the model using a fresh vehicle.

Put simply, spec-ing a "lifetime" fluid isn't saying that fluid age is irrelevant to mileage, it's saying that fluid age (up to the expected vehicle service life) is irrelevant to reliability.

I say again, the improved fuel mileage with new transmission fluid does exist, I agree with you about that. It comes from the improved lubricity of new fluid compared to old fluid and the reduced viscosity of new, uncontaminated, fluid compared to old fluid that is contaminated with wear particles from the transmission.

It does not come from increased converter efficiency (as explained, the lower viscosity of new fluid would actually slightly reduce converter efficiency, but this is so small that it's a non-issue because of aggressive use of the converter lockup clutch even in low gears), and it does not come from reducing clutch pack slip (because the clutch packs in a properly functioning transmission will only be slipping for perhaps a second or two for every few hours of operation and that's simply not enough time to accumulate any measurable mileage gain or loss).

You claim you're not stating your position as fact, but the way you cling to your converter and clutch pack theories suggests otherwise.
 

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I got some things I've heard about the tranny....

from what i have read or saw on youtube. you have to monitor the transmission temp while filling it. supposedly its a very important step. i would have no problem doing that if i new which OBD2 reader can read out the live trans temp... i know its not a cheap one. does anyone know?
also, there is a few. videos on youtube where the change the tranny fluid in a 2012 type r and it doesn't look good...
i looked around for a volvo equivalent fluid and had a difficult time actually soi just ordered it from fcp

and wow you guys really got passionate about tranny fluid.... i almost wanna delete my thread response
 

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it's all good.....i shouldn't get so...involved. Life's too short. This is a good site. Volvo says to set level at a certain temperature range. I'd recommend following that. I would recommend a vida/dice setup ( what year car?) especially if your doing your own maintenance and plan on keeping your car. Some people offer the entire package all setup, at least they use to. Handhelds have been mentioned on here,have you tried a search?......or google?
 

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I have a 2016 V60cc and I think I will probably buy an "icarsoft vol II" to do the trans, the rear brakes and the battery BMS
 

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Although I do not work for Volvo, or any other vehicle manufacturer, I do have extensive experience in statistical process control, gained from working in electronics manufacturing, mostly with semiconductors, but also with printed circuits. The record I keep of miles per gallon, for my 2005 Volvo S60-2.5T, is not a true statistical process control chart, however, it is useful in gaining a sense of what is happening with fuel efficiency over time. From experience, I know that this car will achieve between 20 and 24 mpg driven around town, with trip length under 10 miles. From experience I know that this car will achieve between 32 and 36 mpg when driven on a journey of 100 miles or more, at steady speed between 55 and 75 mph. The gain in fuel efficiency of about 1 mpg, that I reported above, is real, based on observations and records that I keep. This increase in fuel efficiency is seen in driving around town on short trips. Previously, I saw typical mpg of 20 to 23 mpg on short trips, and now I am seeing mpg of 23 to 24 mpg on short trips. The engine was not given a tune up during the period under consideration. There were two maintenance events that would affect fuel efficiency: 1-the ATF was drained and replaced with fresh fluid, and 2-the A/C compressor was taken down, and a bad bearing was replaced. That compressor bearing was making some noise, and the car now operates quietly. It is with considerable confidence that I can say that removing old ATF and replacing it with fresh ATF has resulted in a small but significant increase in miles per gallon. The reason that I chose to use Valvoline "Max Life Full Synthetic" ATF is because it was available locally, at a good price, and also because it was recommended by Valvoline for this specific Aisin transmission. I don't own any stock in Valvoline. I am not particularly passionate about transmission lubrication. The car had 102K miles when I bought it in 2017. It now has 122K miles. I would like to keep using the car, and I am trying to avoid an expensive transmission rebuild. I am of the opinion that fresh ATF will help keep the transmission operating normally. I could be wrong. I see no advantage in operating an automatic transmission with old lubricant that is darkened and thickened with age. Time will tell if I am right, or if my thinking is off track.
 

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I see no advantage in operating an automatic transmission with old lubricant that is darkened and thickened with age.
It is well documented and understood that changing very old fluid is risky.
Generally, if the transmission fluid has not been changed around 60,000 miles, varnish and sludge from oxidized fluid combine with particles from clutch and band wear and create a gummy--almost solid--goo that sticks to transmission parts.

When you change the fluid, the new ATF acts like a solvent to loosen this junk. Like sand, it can wear the friction materials off the bands and clutches causing slippage. Valves--and there are lots of them in the transmission--get stuck open or closed. This causes slow engagement or slippage. Once the buildup is removed, leaks that it prevented begin from seals and gaskets. Any oxidized fluid left behind makes the new fluid more prone to breakdown.
https://www.chicagotribune.com/news/ct-xpm-2000-03-12-0003120058-story.html
 

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^ reasons your local service adviser does not want to change fluid on a 164k car with no history of it being done. as an advisor, im ok with fluid changes if they are done on a reasonable schedule and we arent secretly hoping to cure a problem that will inevitably be blamed on the flush. these are just a couple reasons why i dont like getting into transmission fluid, but will if the customer is aware what it will and will not do for them. plus full synthetic fluid is expensive, it isnt a $99 dollar service like they once were on the ole chevy.
 

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Discussion Starter #79
Alright guys, I actually decided to go to a local shop to get my Transmission Fluid Changed (not flushed). When I went in, I had 80675 miles on my Volvo S60. They drained what came out and put in the same amount. The fluid was very dirty so it was a good thing that I didn't wait any longer. I have since driven over 200 miles and I haven't had any major issues with hard shifts, if anything it made the shifting much more smoother. If anyone has around 80k miles or less and hasn't changed the fluid, it does improve the shifting and it's noticeable. Also the mechanic that did the job recommended every 30k miles to change the fluid (not flush). It was around $70 dollars labor and $96 dollars for the fluid.
 

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So I just made the dealership drain and fill my transmission since it seemed to have lost it’s smoothness. I’m at just under 40k miles and they insisted that it didn’t need it and it was life time fluid. I had them do it anyway and OMG it’s like a new car. My car is a 2017 S60 Inscription AWD with Polestar Optimization.
 
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