Talked to a transmission rebuilder in Tulsa, changed my whole approach
Ngl, I was killing time at a parts counter last Thursday and this older guy, Dave, started talking about how he's been rebuilding automatics since the 80s. He said most failures he sees aren't from wear, they're from cheap fluid and lazy filter changes, like people hitting 60k miles and thinking they're fine. That hit different because I've always just followed the manual, but he showed me a valve body with varnish on it from a 2015 truck that was serviced on schedule. Has anyone else had a pro change how you think about basic maintenance, or do you all stick to the book no matter what?
Did Dave say whether he recommends a specific fluid type or just more frequent changes? That part matters more than the interval, since some of those "lifetime" fluids are the real problem. Curious what the shop guys actually put in when they want a trans to last.