I have a o3 expedition with 180k around 45 to 55 mph over this weird rumble for about a split second but it's pretty consistent I would imagine that it's the trans but I have no idea I hoped it wasn't but was wondering if anyone else had any experience with issue

 

What have you checked so far? A nondescript rumbling could be a number of things, including tires, wheel bearings, or U joints.