I have a 2010 Forester XT with 140k miles and 2013 Lexus GX with 90k miles. Both have never had the transmission fluid changed, looking for opinions on doing this, and do they also have filters that need to be changed as well? Thanks.
You would be ok to.do a drain and fill for sure on the Lexus. If it has a filter, just replace it.
On the Subaru, if it is a manual I'd do a drain and fill. If it is an automatic I would drain the old fluid, change the filter, and put the old fluid back in. It's gone too long past the 60k recommended time for changing and moving to all new fluid now could cause problems.
Forester, in my opinion, is to far gone. Ride it out till it blows. The Lexus I actually would do a drain and fill replace filter if it has one. You can check if it does from manual.
I'm not a big fan of "run to fail." Proper preventive maintenance trumps the proverbial head-in-the-sand.
One analogy that I find useful is this: It's like brushing one's teeth. If one has not brushed one's teeth in six month, that doesn't mean it's OK not to do it, ever again.
Having said that, here's a few pointers:
1. Drain and fill only. NO FLUSHES. Ideally, this should NOT be offered to you, because both GM and Hondas have issued specific TSBs that warns dealers that flushing voids warranties. However, it's easy and cheap for the service people and potentially disastrous for your Cruze. NO FLUSHES, under any circumstances. DRAIN AND FILL, only.
If you want to drop the pans and change the filters, that's obviously OK. According to thecarcarenut (a Master Toyota Diagnostician on YouTube), he's rarely seen to change the filters the need on Toyota products. Your choice on whether to drop the pan and change the filters.
I've no direct experience with the Subaru, but I'm sure you can find video demonstrations of how this gets done on a Subaru.
2. Use the right fluid. Mixing fluids can also be disastrous for a transmission. OEM fluid only.
3. Educate yourself on the procedure. (There are YouTube videos on this, if you're considering DIY). It's always a good idea. For example, changing the automatic transmission on a Lexus of that era is a bit more complex. (See here for an explanation: http://www.agcoauto.com/content/news/p2_articleid/345 ). There are video tutorials on 2010 and beyond tranny fluid changes on a Lexus and Subarus.
Here's the key notion: The point is not necessarily to remove all the fluid, in a drain and fill, but to remove a considerable portion, and replenish the fluid with the general lubrication additives as well as the additives that keep the seals pliable.
Good luck.
