Old transmission fluid change... Risks/Benefits... 2006 XC90

[vertu]

2006 XC90 AWD, 5-speed transmission
13 y/o car but relatively low mileage for such age, 155K

I only changed the transmission fluid once in the past at 50K…that was 10 years ago. I understand that Volvo official guidance is “lifetime” fluid and no changes under regular usage, but I also read that it should be taken with a grain of salt, so my plan was to change it regularly….except now I let it go for over 100K and about 10 years on the same fluid since the last change. Despite that, my mechanic tells me the fluid is still pinkish and in good condition.

Opinions so far:
- My trusted Volvo mechanic: you can change it if you want to, no risk, up to me
- Dealer: don’t change, too many miles since the last change, just leave it, you’re risking ruining the transmission…

I would like to keep this car for as long as I can…. hopefully beyond 200K / another 3-4 years, so my desire is to keep the transmission in best shape for as long as I can. So what’s best? How often do you guys change the fluid in this 5-sp transmission?

If I can be confident the change can only benefit the transmission, I would do it. But is the dealer right, would I be risking it more by changing it at this point? I suspect the dealer could be dismissing the car as too old and destined to fail soon one way or the other, and advises not to do anything based on that, but the car is otherwise is good shape (new timing belt, PCV serviced, etc), so I’m hopeful it will last for longer term…

[SuperHerman]

Change it.

Did the dealer even look at the fluid?

From the sounds of the fluid condition, from your mechanic, your transmission is in great shape. As the transmission clutch packs wear the fluid turns dark due to particulates. It also starts to loose its lubricating, heat dissipation ability and other benefits. If your fluid is still "pinkish" your clutch packs have not worn a great deal (although I don't know what it looked like 100k ago). Still if it is "pinkish" after 100k - change it.

The theory is when it is black and gritty, that grit is what is allowing your clutch plates to perform. You are not at this point. The grit allows a transmission on its deathbed to work (barely), but it also causes excessive wear on everything. Don't go there - change it.

[wanderdüne]

Assuming that this is the 2.5T. You can just do staggered partial drain and fills on this one relatively easily. On mine, with the car off, I just drain the pan, measure, then add back that amount of new fluid. A few weeks later, do it again four times in total. I feel like it's a lot less dramatic than doing a complete change and as long as the fluid seems ok to start with, I think it's the way to go. Maybe just a superstition for me. The Mobil 3309 is inexpensive enough that 12 quarts or so isn't the end of the world.

[SuperHerman]

For 2.5 Drain and Fill is a great way to go. Do two within 200 miles of each other and then do it every 20k or so. If not the 2.5 do what the mechanic fields best, but I wouldn't do a powerflush (unless he will warranty the transmission for 5k miles).

As to transmission fluid - think of it as brake dust. First remember the transmission is a closed system - it does not have outside contaminants like the engine and its oil. The brake pads are your clutch disks. As the clutch packs engage and disengage they wear and tiny bits of the disks are worn off just like on your car brakes. The transmission fluid washes away the "brake dust", keeps things lubricated and cool as well as applying the pressure needed to change gears as it works with the solenoids. As the "brake dust" builds up and mixes with the fluid it turns black. The "brake dust" is gritty. Not only does it cause premature wear it can cause sticking of the solenoids. That is why clean fluid is best. Tranny fluid, like engine oil, also breaks down with heat which is another reason to change it.

[MoVolvos]

2006 XC90 AWD, 5-speed transmission according to IPD has the 2.5T motor and the transmission is the AW55-5x

https://www.ipdusa.com/

If that is the case this video should be about the same in terms of doing a flush.



I've used this method on more than a dozen cars and never had an issue. Currently I am running a trans-cooler only on my 2003 Odyssey completely bypassing the radiator and even during the summer the engine temp needle is below half.

Son's daily for school now and as the weather is getting cooler he noticed the engine temp is only slightly above 1/3 so we will need to block the trans-cooler fins for winter.

[vertu]

Thanks for all your replies. Yes it's a 2.5T. The dealer did not even look at the fluid, just said to leave it alone at this point.

The suggested "staggered" approach makes sense...to let the transmission acclimate to the new fluid more gradually. I'll go with that.

My independent Volvo mechanic tells me his fluid specifications exceed that of the genuine Volvo stuff. Is it Ok to go with what he uses, or is it safer to put exactly the same genuine Volvo fluid that's been sitting in my transmission for the last 10 years? (I assume it was genuine, since it was changed at the dealer last time)

[MoVolvos]

My independent Volvo mechanic tells me his fluid specifications exceed that of the genuine Volvo stuff. Is it Ok to go with what he uses, or is it safer to put exactly the same genuine Volvo fluid that's been sitting in my transmission for the last 10 years? (I assume it was genuine, since it was changed at the dealer last time)

Dealers don't always use Factory Fluids. When I was at Acura they used Castrol. I think they still do. Ask your Indie shop what brand they are using before making a decision.

[ggleavitt]

I vote 100% change the fluid, you'll be happy that you did.

Transmission fluids can be a touchy subject and if you use the wrong spec you'll not be very happy. The AW5x transmission uses straight up JWS3309, folks can say what they wish about alternatives but for many years the most common fluids that have been noted for replacement have been OE, Mobil 3309, and Toyota T-IV. Toyota T-IV often ends up being the least costly, followed by the Mobil product. I've never seen a compelling reason to buy the OE fluid (or any OE fluid other than coolant and AOC for that matter). There are some mentions about Idemitsu over the last few years and you probably cannot go wrong with Aisin Warner but the above are what I've mostly seen used.

I have personal experience with Mobil 3309, having done 4 of these flushes between my vehicles (3x AW5, 1x TF80).

[Roger_850T]

I vote 100% change the fluid, you'll be happy that you did.

Transmission fluids can be a touchy subject and if you use the wrong spec you'll not be very happy. The AW5x transmission uses straight up JWS3309, folks can say what they wish about alternatives but for many years the most common fluids that have been noted for replacement have been OE, Mobil 3309, and Toyota T-IV. Toyota T-IV often ends up being the least costly, followed by the Mobil product. I've never seen a compelling reason to buy the OE fluid (or any OE fluid other than coolant and AOC for that matter). There are some mentions about Idemitsu over the last few years and you probably cannot go wrong with Aisin Warner but the above are what I've mostly seen used.

I have personal experience with Mobil 3309, having done 4 of these flushes between my vehicles (3x AW5, 1x TF80).

I agree with all of this. I'm about ready to do it again on my XC90.

I think the dealer says not to do it primarily for liability. Volvo NA says don't do it, so if they do nothing and it breaks, they are covered. However if they change the fluid and it breaks, then you'll want them to buy you a new transmission. But I've seen some pretty horrible fluid come out of old transmissions, and seen a fluid change recover at least one that was otherwise looking terminal, so all in all I think changing the fluid is a good thing.

Some of the concerns about changing fluid come from people who do it at Jiffy Lube, where they have a machine that forces the new fluid in under pressure. I suspect that process can cause problems. But if you search for the "Gibbons Method", I have used that successfully several times, and will do it again.

I use the Mobil 3309, mostly because it meets the spec and can be found for an affordable price. The best I have found is at Summit Racing. https://www.summitracing.com/parts/mob-123062/overview/ If that ever becomes expensive, I'll look at the Toyota version.

Do you have a copy of VIDA? There is a counter in the transmission computer that keeps track of how long the fluid has been in there, and what the thermal cycles of the fluid have been. This helps the computer manage the shifting for smooth results. You'll want to use VIDA to reset the counter and tell the computer it's got new fluid. If you want to, you can also go through the whole re-learn process, which can be helpful if you're having any trouble with flares or harshness during shifting.

Roger

[abscate]

Despite that, my mechanic tells me the fluid is still pinkish and in good condition.

Opinions so far:
- My trusted Volvo mechanic: you can change it if you want to, no risk, up to me

And your mechanic gets the prize. Do the slow, incremental drain and fill method over the next few months.

You can never 'break' a transmission with an oil change - what you do is just make the already present damage manifest itself, which it will anyway.

Its like giving rabies to a terminal ebola patient, then blaming the dog.

(Where did that come from?)