driveline hum

So yesterday I took a 300+ mile round trip drive with my truck and along the way it developed one hell of a humming noise coming from the driveline.
It seems to be worse at slower speeds and when slowing down or accelerating. Its consistent at speed. Driveability isnt affected at all, I was still able to drive 80+ mph without an issue.
A few weeks ago I got my tires rotated and after that I noticed a slight hum when slowing down to a stop but I thought it had something to do with the tires because I hadnt gotten them rotated in quite a while. Apparently thats related to the current issue and its gotten worse.
What could possibly be the cause?
'06 F150 XLT Supercab, 5.4, 9.75" limited slip rear, 4x4

pinion bearing, or wheel bearing would be first to check.

Cam phasers duuka, cam phasers.

I honestly dont know how to check if a bearing is shot.

Am I risking it driving the truck? It seems to ride and drive fine except the noise right now but it definitely got worse.

oh shiiit! unplug the ecm

no, that makes the motor tap/knock and only affects '04-'05’s. Mine’s an '06.

both will get louder, is the noise worse turning to left or right, or under acceleration.

It was a joke between duuka and myself pjb.

acceleration and deceleration. Constant at speed but not as bad/loud. Dont notice it while turning.

Jack it up, and pull/push on the tire in various ways, checking for excessive play, and rotate it both ways, listening for noises. Do the same with the driveshaft. Oh, and this is what you get for buying a junk Ford, my truck>your truck

that usually is what a pinion bearing sounds like when it’s on it’s way out.

Could always run it on jackstands and listen for it

sounds like a pinion… get under the truck and see if you can move the yoke back and forth or in an out AT ALL. the movement will be very very light if you can even move it at all. usually if you can feel it in the yoke its way past too late.

Is replacing it a big job? Probably not something I want to do myself in case but Im just wondering how much Id have to spend.

Ill have to check it when I get back later on.

And I dont think one bearing going bad at almost 93k makes it a bad truck.

even better get it on stands and have a buddy accelerate and decelerate. put a prybar up to the diff where the pinion would be and listen.

Could there also be debris in the gear oil?

take it to wayne

THATS WHAT I SAID BASICALLY FOOL

yea if its a bearing coming out there will be MUCHO silver in the gear oil, it will be dirty but it will have almost a shimmer to it… hard to explain…

I had it changed at 62k when the seal leaked.