I've driven the truck about 400 miles since changing the oil, and I've observed two things: a) drop in oil pressure b) improved fuel economy The oil pressure gauge used to sit on the last hash mark before "H", and never budged. Hot, cold, winter, summer; it didn't matter. For a long time I thought it was just a dummy gauge, or "glorified idiot light." That was with 15w-40 or straight 30. Now after 30 minutes of driving, even at cruising RPM (3,000 rpm on the highway), it drops down to 3/4 and stays there. Might drop a tick down to about 2/3 at warm idle. Soon I will put a mechanical gauge on it and see what how the factory gauge corresponds to actual pressure. That'd be a whole lot more helpful than just "L" and "H" or somewhere in between My last run of both tanks gave me 10.54mpg. Before now, I haven't made it past the 10mpg mark, it would average about 9.5 mpg which is about 180 miles per tank. That's almost a ten percent increase, which I'll certainly take. Obviously I'll have to run a few tankfuls to get a true before vs after average, but my drive doesn't change (125 miles per day, Mon-Fri), so this looks promising. Nothing unusual noted such as increase in engine noise / NVH. Difficult to tell if it's improved cold starting at all, as it hasn't dropped down to the teens, or single digits where it would really labor to turn the engine over before. Time will tell on that one.