We own a 2009 manual Elantra Touring. My husband will not shift into 5th gear untill he has reach 65mph. No matter what. If he is not at this speed he will not shift and use 5th gear. I've been driving manual a lot longer than he has, and was taught to shift to fifth gear as soon as I hit my cruising speed, Be it 45 or 50 on main roads, or when getting on a highway and shifting at 3.5 to 4 RPMs to match traffic, which means I'm shifting into 5th gear at about 65 mph. From what I understand of car, I feel like this is actually hurting the engine. Is this so or is it okay for this vehicle to be driven in 4th untill reaching 65mph?