comments:
Trans fluid service on the 2017 Forester XT would be approximately $250-400 at a shop or dealer. More expensive at dealer, less expensive at an independent shop. A lot of that comes down to the cost of the fluid, it's like $20+ a quart and you need something like 8qts. In-line filter, not sure about that one. Maybe $2-300? The filter itself is only like $20-30 and you just need to get some trans fluid oil lines and clamps. I did it myself but it wouldn't be crazy hard for a shop to do it. If they are already familiar with Subaru's and know how the lines are routed between CVT heat exchanger and the transmission then it'd be <1hr of shop time. This is the inline filter I use: https://www.amazon.com/Magnefine-Magnetic-Inline-Transmission-Filter/dp/B0781B5BR3 It will need to be replaced everytime the transmission is serviced thereafter (kind of like an oil filter). The OEM trans cooler part number is 45512SG000, but it's hella expensive. I went with an aftermarket unit. This is something that you should talk to an indie Subaru shop about. The dealer will have abso-fucking-lutely no idea what it is or what to do with it. I used a Hayden 698 with a built-in thermal bypass so that fluid doesn't flow through most of the cooler until it is warm enough. I drive in a northern clime that gets well into the negatives, no issues. If you were going to service the trans you could get the shop to do all of this all at once I would think that it'd be <$1000 since they're doing multiple things at once. Installing the trans cooler and the filter requires removing and adding at least a bit of trans fluid, so it's better to do it before you're going to drain older fluid and fill with new. But yeah once the TR690 trans on the 2014-2018 Forester XT's reach 60-70k miles it's kind of a crapshoot whether you'll need a new valve body or not even if you do a fluid change. At 40k miles it's just a little past the ideal change interval so it should not be too late.