Here's another of the endless GL-4 - GL5 articles.

http://forums.nicoclub.com/gl-5-transmission-fluid-t312877.html#p3367628

As ususal, there are amateur opinions on both sides. I wish an active PROFESSIONAL lubrication engineer with a major lubricating oil company (NOT somebody with a single product they're pushing) would weigh in on the subject with an in-depth description of the issue, and the science behind it.

Ray