I have an 18 year old Toyota Sienna my father gave me about 1 year ago when my wife and I moved back to the states. My father and I both take very good care of our cars, most regular maintenance done ourselves by the book and on time. The car has been in 2-3 fender benders over its lifetime, but no major collisions, and no major maintenance done on it (even the AC is original). It's got 130k miles on it.

I could definitely afford something new now, but the car runs well. The only issue I notice is that when accelerating to highway speeds, there's some kind of gyration sound. When we were moving to our new home in Florida, I used the car to tow UHaul's biggest trailer for about 1000 miles (within rated limits); I'm wondering if I stressed the transmission and it's the beginning of a slow end for it (never had a trans failure before, so no idea). Plus, we're in Florida now. The humidity, salt, and the more frequent use of AC would probably start causing issues with some part of the car sooner than usual.

It's not quite on topic, but am I right in thinking about selling? Right now I could probably get $4-5000 for it tops since it looks and works so well. But if transmission issues start to become noticeable, I'm sure that figure would deteriorate quickly. And if it fails completely, I'd have to pay money to get rid of it and have to very quickly buy a new car at possibly not an ideal time.