Ford F150 - give it to me straight.

so I bought a 2005 XL f-150 hated that truck got rid of it last week. bought a 2004 xlt supercab power everything truck is very clean looks like it was taken care of, BUT I bought it off a lot. and it has 162000mi and i paid nine Gs and now driving down the freeway it sounds like my tires are humming but there stock tires and it only does it 50 mph and above and all i have to do is touch the excelator it seems the harder i press the excel the louder it gets again it just sounds like the rear tires its not an eggresive tire . any idea's.

could be almost anything, wheel bearing, rear differental, wind on mudflaps, mirrors, bumper, or wind on something else, as it hard to tell with out hearing it.
Have you checked you differental oil, is it clean, that a lot of miles depending on how loud it is,

No vibration, just a hum?

Good luck that was my two cents.

do you feel a shake or vibration? tires may need to be balanced.

cud just be sh*t tires cheap tires wine on the highway or if they are old and hard they will wine on the highway thats what i wud say cuz if u cant hear it in the city then its probably not a wheel bearing or anything like that. i duno stick ur head out the window when ur driving slower nd see if u can hear it.

maybe you should have kept the '05