I am by no way a professional at all, but I have a little experience that may help.
My 89 S10 Blazer, in 2007, had its tranny taken apart by my mechanic, a Jehovas witness. He aaid there were metal shavings, and he wiped them out, and it was fine. From his account, a series of gears constantly rotating is supposed to do that. That sounds like brake masters wants to break your wallet.
In most newer vehicles, no throttle in gear is better han coasting in neutral. I do not know this for FACT in ALL situations, but It was explained to me that the computers now know how to coast in gear, and when we people think we know better and put it in neutral, the tranny and engine are thinking 'oh crap, what's going on' and use more fuel to be ale to adjust faster.
Example: if you are on the highway, 55 mph. In gear, you can coast and use little fuel not accelerating. If you are in neutral, the tranny may be expecting you to suddenly drop to 2nd, 1st, whatever.
But I'm sure it varies. Just DON'T go off of rpm to judge. When I shift into 1st to go down a steep hill at 35, I approach 5000 rpms. But my mpg are not the 3-7 mpg I get when I am at 5000 rpm getting on the highway in first gear lol, rather 45+
my point is, every car is different, and you can only believe half of what you see, and nothing that you hear. I hope you find your answer and some peace
