Well maybe that was the "last straw" but by no means should flooring it on the freeway have to = 4th gear death. But that's how it is when they get weak. After the new one is in you should feel free to use 4th as you please like a normal car lol.
That's why I want to change mine while I'm there changing my pcs. So I can stop worrying about not giving it too much gas in 4th. I keep thinking, now I hope I'm not going to see my rpm's jump up and not go back down after giving it some gas. Driving will be a bit more fun once I don't have that on my mind.