Hi,
re: 2005 Yukon XL, 2500, 8.1L, 4wd, 4.10 rear, 4-L85e
tires: Blizzak W965, LT265/75r16
Last Nov/Dec 2017, bought a used Yukon and I too am stuck with a vibration.
- it starts around 55mph <90kmh>
- increases in sound and slight physical shaking (vibrations) til 60mph <100kmh>
- then...