Looking at a 2011 Escape 3.0 AWD has a noise
 

Test drove last night in the rain. Owner said the newish tires were loud. I heard the noise he was referring to. But after thinking on it some I am wondering if it could have been the PTU making the noise. Car has 78k on the OD. I've been through this with the wife's Edge AWD but it didn't make a noise till it was too late and it wasn't aggressive tire noise. I am not finding ANY info on this forum about the PTU's on the Escape but outside of the forum there is some mention of it. Told the guy we would take it on Monday but I've not given him any money yet. I need some advice on how to tell if this thing is a DO NOT BUY kinda car. Thanks