Eco Boost Owners - Anyone using a Tow Tune?

Wes Tausend wrote:

In this regard, I've heard there is very little frictional difference (syn is just slightly better) between modern straight petroleum oils and synthetic and I tend to believe that in spite of predictable product hype.
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I've done the comparison. I have a rear diff temp gauge, so it's pretty easy to compare. Filling with a high-end conventional raises my average diff temp by 30 degrees. It was enough of a difference I did not keep the conventional in there very long. I've maxed out my temp gauge on synthetic, so with conventional it would have maxed out much sooner. The gauge stops at 250F so that's when I stop (only had to once.... Towing out of death valley pulling 15,000 pounds). I know the oils are rated higher than that, but there's enough variation I don't want to guess, nor do I want to guess how much hotter than 250F my diff is, especially since that's the flowing oil temp (ring gear slings it onto the sender) which means my ring & pinion are much hotter.

I did not have the temp gauge when I had the 9.75" setup, so I cannot compare how changing to the 10.5" setup affected temps. (axle housing is the same. Ford stuffs the D60 gearset into the D70 housing, so upgrading diffs does not require upgrading the axle in some of the vans)