I will agree, it is much easier to replace steels than to properly refinish them. I constantly ask myself, why am I taking so much time to refinish these steels? I should just have the customer pay for new ones. But, I get caught up in the idea of trying to save the customer what I can.
The idea that steels should not be refinished started around the time that high energy frictions came onto the market. I do agree with the notion. But I still pick when I feel a refinished steel will work and when the steel should just be replaced. When the refinishing is done correctly, and used in the correct application, the surface of the steel smoothes out quickly. You'd never know it was refinished.
On the other hand, it is absolutely correct that if the finish is not done right it will prematurely wear the friction material. I've witnessed this with transmissions that obviously had the mexi method used on them. So why do so many transmission technicians religiously use the mexi method? Simple. It is a very quick way to refinish steels. Hand refinishing steels is very labor intensive and there is no money in it for the rebuilder for the time that he spends doing it.
After you've done transmissions for over 20 years, you learn what will live and what won't. When I first read the articles about the preferred finish for steels, I thought to myself, wow, there's enough people out there ruining friction plates with the wrong finish on the steels that they had to come out with a technical article to try to put a stop to it. Don't get me wrong. I completely agree with the move to do that. Very few technicians are willing to take the care to refinish steels correctly. I also realize, it's a good way to increase sales of steel plates.
One place where I feel that a slight finish on the steels is very important is on the direct steels of a 200-4R that is intended for high performance use. Some people have learned that it is best to put some easy miles on a 200-4R first rather than just jumping into some full blown passes on a fresh unit. The reason for this is to bed in the friction elements to increase surface area contact between the steels and frictions. The more surface area contact, the better the holding power of the clutch pack or band. If you take a new friction and look at the surface under a microscope, you would see peaks and valleys. Not a perfectly smooth surface. The bedding in of the material smoothes the surface and makes a smoother surface for more contact area. People that take the time to properly bed in their frictions notice the shifts get quicker. A clutch pack that has been bedded in is less likely to glaze under high loading. It's really not that much different than bedding in new brake pads before any planned heavy towing.
The light finish on the steels helps to bed in the frictions quicker. If you were to remove and inspect the steels after a bedding in process, you would find that the steels were just as smooth as a new off the shelf steel and there would be practically no loss in friction thickness.
