Vibration/Rumbling above 65MPH

[anthonycronk]

Hello all! My 2000 Eddie Bauer 5.0 Explorer has a pretty intense rumble/shake feeling when going over 65. It doesn’t shake the steering wheel but it’s mostly under the floorboard. The shake also happens in higher gears around 2-3000 rpm’s. At low speeds there’s a loud squeak coming from the back (what I think is the ujoint or possibly differential bearing)
The rear drive shaft has some play between the slip yoke and the rest of the shaft, is this normal? The actual ujoints don’t seem to have play but Im going to replace them anyway.

Parts I’ve replaced:
All shocks
Lower and upper front control arms
Both front Wheel bearings
New tires and wheels balanced
Newish front cv joints
Brakes all the way around
Tie rods with an alignment
Transmission valve body replaced with a rebuilt unit/ all sensors replaced
Rear differential fluid changed
Front drive shaft rebuilt
Videos of the squeak and me driving on the freeway. Please let me know what you guys think this could be. Trying my best to get this car comfortable on the freeway before winter.

 

[Josiah Welch]

Are the tires balanced well?

 

[wollimann]

At low speeds there’s a loud squeak coming from the back

For me it sound like a dry/worn U-joint, had similar sound.