I recently (08/20/16) purchased a used 2013 XSport with 28,500 miles. The vehicle was previously a single owner private lease. The vehicle seemed entirely stock, so I have no reason to suspect that the PTU fluid wasn't the original. At 29,948 miles I swapped the engine, transmission (drain and fill twice), and PTU over to Amsoil synthetic. I sent in the original PTU oil for analysis.
This is their summary (I had asked if they had a virgin sample of Motorcraft 75W-140 for comparison). The full report is attached. Try another change at 10,000 miles?! So much for lifetime fluid...
MICHAEL: No, we don't have a virgin sample/TAN in our database, but it's a pretty typical gear lube in terms of additives. Wear is quite high here. We looked through all of the Ford PTU's we've seen. Half looked like this (or worse) and half looked like our averages. Note aluminum -- that's from the assembly. Maybe some of it's normal accumulation/wear-in, but the oil change was probably a good idea, to keep the oil from getting abrasive. Chrome is likely from steel, copper is from brass/bronze, and silicon is probably just a sealer. The TAN read 4.5. Try just 10,000 miles.
On a side note, after initial PTU draining, I didn't really suspect I had an issue. The fluid was dark and had that gear oil stink, but it was still "oil" (unlike some of the other posts I've seen). Still, I thought I'd be safe and send it in for anaylsis. I refilled with Amsoil and drove for 20 miles before immediately re-draining. In just 20 miles the new fluid was black again, although it did not stick to the side of the glass container like the original fluid. I'll change this fluid again in another 10-15k miles and send it back to BL for another analysis.
