So I got a new to me 2006 Chevy Colorado 4cyl auto, 2wd. I was wondering if I should change the trans fluid an filter since its at 74k miles and it's still pink. And i don't know what type of motor oil the original owner used should I use synthetic anyways or just go by what the manual says?

Do the trans. Switch to synthetic if you want longer drain intervals. I really like pennzoil platinum right now based on the data i've seen. 5qt jugs at walmart are cheap.