Hi and welcome to the group! Glad to have you here. This forum really is a ton of help. With a little bit of research you can find an answer to all your questions. Have fun surfing around!
It's definitely nice when you're the original owner and know the maintenance that's been done on it. We bought our 2008 Armada when it was almost 10 years old and had almost 100K miles on it. But luckily, it seems like the engine and transmission are still in good condition, but the suspension on mine needed quite the overhaul.