Originally Posted by JCL

Then, I expect that during teardown a cause of failure will be found. If that failure relates to a hydraulic circuit that has debris in it, I think a reasonable hypothesis will be that the powerful detergents in the new transmission fluid acted as they are designed to do, and cleaned out the sediments, where they lodged in the small passages of the valve body. Cleaning out the valve body now may in fact restore the functioning of the transmission.

I don't think the example is meaningless, but for a reasonable conclusion to be drawn, I would expect something along the lines of the above. Is this the statistical proof based on a sample of 100,000 that you asked for? No, but it is how trained technicians work, and it is the best we have.