2005 XC70 transmission oil

[Grudzibp]

Hi everyone, I have a 2005 XC70 with 175K miles on it. I bought it with 110K. It runs great! I've heard that changing the trans oil on such an old and high mileage car can do more harm than good. I haven't changed it yet and not sure if previous owners did. The dip stick color is not terrible, but definitely not super clean either. I drove the car about 5K miles per year and hope to keep it for about the next 7 years. Would you change the trans oil or not mess with it? Why or why not?

[Krons]

Strong opinions on both sides for drain and fill vs flush. General consensus is drain/fill if fluid is dark brown, flush if a tinge of red, and if burnt smell—leave alone. Logic being if dark/burnt new too slippery fluid could cause clutches in trans to slip.

That said I’ve done a cooler return flush on an 02 S60 and 05 S40, both at 150k. The S40 shifted a little funky at first but settled into smooth shifting. Both took about 3 gallons of Valvoline Maxlife ATF before the fluid came through clean. For drain and fill some/most may prefer 3309 fluid to minimize mixing. And with Maxlife price going up Mobil 3309 isn’t much more expensive.

With your situation (not driving a lot) the drain and fill may be easiest, same as oil change the toughest part is getting a funnel and/or hose to the trans dipstick hole.

[vtl]

Drain and fill, use Volvo 1161640.

[erikv11]

I'd change it. Either method will do for your car, as Krons said and (vtl recommended), the drain and fill will be easiest.

[greg850r]

Drain and fill, use Volvo 1161640.

I would do a drain & fill when I change oil the next 3 times.

[leapdragon]

100% change. There is no user-serviceable filter on this tranny, just an internal screen that's pretty small and blocks fluid flow when clogged, so if you gunk it up, the whole thing grinds to a halt and tranny has to come out for rebuild/replacement. The solenoids in the valve body also tend to get "sticky" with gunk and it is not at all a fun job to replace the valve body IMO, not to mention it's at the spendier end of Volvo parts. My policy for the AW55 units is keep the fluid as clean as reasonably possible at all times. I do a full fluid exchange every 30k with Mobil 3309.

While you're paying attention to it, consider splicing a Magnefine 3/8" trans filter into the return line (return line comes out of the top of the radiator, fluid flows from top of radiator back into transmission case, note that these filters are directional) so that you stop any debris or gunk *before* it gets back into the transmission case in the future, to keep that internal screen as clear as possible, and so that you have a trans filter that you actually *can* replace every fluid exchange.

The fluid exchange method I'd recommend is the pump-out, refill method. I think there's a last name that people use to refer to it, but I forget it. Basically—you unplug the trans return line from the top of the radiator and run a hose from the top of the radiator into a bucket instead with quarts marked off on it. Turn on the car, run it long enough for 2 quarts to be pumped into the bucket, then turn off. Refill two quarts. Turn on car again, run out next 2 quarts into bucket. Stop and refill another two quarts. Run 12 quarts this way and you'll have fluid like new in there. Doing this every 30k for me ends up being about $30-40/year/car once you do the math, which isn't bad at all.

If you plan to do all this stuff, have on hand:

- Spare transmission return line in case you mess up the splice (junkyard $10 item)
- Magnefine 3/8" filter
- 3/8" hose clamps for either end of the filter
- Spare return line clips (they WILL break regularly but are cheap): www.amazon.com/gp/product/B013Z0DC5G/
- Spare o-ring set, also cheap: www.amazon.com/gp/product/B07CTNMVQM/
- $10 dishwasher drain hose from hardware store (fits perfectly over the transmission return line hole on the radiator)
- Graduated bucket marked with quarts, like $0.99 each at the hardware store in the paint section
- A long, narrow-nosed funnel that fits into the dipstick tube
- 12 quarts of Mobil 1 3309, Toyota Type IV, Idemitsu Type TLS (NOT LV or FE), or Aisin Type T-IV
- A partner to help hold the hose into the bucket as you turn off/turn on

Note about refill: there is no refill port. Don't go taking off bolts trying to find it, as one of them routinely screwed up by non-Volvo shops *looks* like a refill port but actually holds a band clamp in place that can't be reattached without disassembling the transmission. If you pull that bolt trying to refill, you'll lose a gear (3rd I think?) and need a rebuild. Refill through the dipstick tube.

Final note about the fluid—don't let anyone talk you into using a "general" transmission fluid with these units like Valvoline MaxLife or something else that's "JWS3309 rated." In my experience, these transmissions want the original stuff as specced by Aisin-Warner or they'll ultimately start to shift wacky and hard and may start to slip, which does damage to your clutch plates and solenoids. Basically that means either the Volvo OEM fluid or one of the four types above, whichever is available to you for less.

Also, if you have someone nearby with a VIDA/DiCE setup, you should also in theory reset the transmission fluid counter each time you do a fluid exchange as the computer uses it to adjust some shift parameters based on the age of the fluid, but I think in practice most have also had good experience without bothering.

[vtl]

100% change. There is no user-serviceable filter on this tranny, just an internal screen that's pretty small and blocks fluid flow when clogged, so if you gunk it up, the whole thing grinds to a halt and tranny has to come out for rebuild/replacement. The solenoids in the valve body also tend to get "sticky" with gunk and it is not at all a fun job to replace the valve body IMO, not to mention it's at the spendier end of Volvo parts. My policy for the AW55 units is keep the fluid as clean as reasonably possible at all times. I do a full fluid exchange every 30k with Mobil 3309.

While you're paying attention to it, consider splicing a Magnefine 3/8" trans filter into the return line (return line comes out of the top of the radiator, fluid flows from top of radiator back into transmission case, note that these filters are directional) so that you stop any debris or gunk *before* it gets back into the transmission case in the future, to keep that internal screen as clear as possible, and so that you have a trans filter that you actually *can* replace every fluid exchange.

The fluid exchange method I'd recommend is the pump-out, refill method. I think there's a last name that people use to refer to it, but I forget it. Basically—you unplug the trans return line from the top of the radiator and run a hose from the top of the radiator into a bucket instead with quarts marked off on it. Turn on the car, run it long enough for 2 quarts to be pumped into the bucket, then turn off. Refill two quarts. Turn on car again, run out next 2 quarts into bucket. Stop and refill another two quarts. Run 12 quarts this way and you'll have fluid like new in there. Doing this every 30k for me ends up being about $30-40/year/car once you do the math, which isn't bad at all.

Only a fraction of fluid flow is diverted towards the cooler. The colder ATF is, the lesser its volume is going to the cooler.

Also it makes no sense doing ATF change this way, as the majority of fluid still circulates within the transmission and mixes in torque converter and sump. Draining sump and refilling with the same amount is the quickest, less messy and the most efficient. Can do 2-3 drain&fills using the same 12 quarts. After the third fill you'll have about 85% of clean fluid in the transmission.

100% can only be replaced while rebuilding the whole transmission.

[leapdragon]

Maybe so, but even though there is mixing, 12 quarts in you look like brand new fluid (which doesn't happen by quart 3-4), and you only have to do it once every 30k (~3 years for me)—without getting under your car. So the return line method feels much less messy to me, but maybe that's because I've done it so many times and have all the right tools.

Each to their own. Point being—no, don't avoid cleaning up the fluid some, even at 175k.