I have a 2001 Buick Lesabre with 145k miles, mostly highway. As far as I know the Transmission has never been flushed. Do I need the service? Do I need the screen replaced? It runs great and has no problems. I’m concerned about the story we’ve all heard from someone that had a fluid flushed and had a bunch of problems shortly there-after. Thanks.
You’ll get a lot of different “stories” about that, most of them will be to not flush the transmission. You should just have a reputable trans shop drop the pan, clean, & replace the filter. But this should just be done about every 30-40K or so as regular maintenance (or you can look in the owners manual and follow what it says - it will likely give a longer interval).
If the trans is having some problem, though, this doesn’t “fix” anything, though cleaner running fluid might help some minor problems.
I would consider a fluid change, but I don’t think I’d let anyone flush it at this mileage.