Good luck with this. Be sure to let us know what happens. hopefully they find the issue pretty easy. Ball joints, Tie Rods, Axle shaft assemblies. Those are the most obvious culprits I can think of right now.

 

I have to take it back in Monday and leave it for a day or two for them to TRY to find the problem.

 

Only thing I can think of is that when you had the new tires put on and it was put on the lift maybe the suspension dropping caused somethng to give. Good luck at the dealer I hope they find it.

 

Couldn't make it in today. Gonna take it to the dealership tomorrow and let them keep it for a day to try to figure it out. Wish me luck!

 

Update...
Well after a $70 "diagnostic test" the dealership mech says the vibration is coming from bad u-joints on the drive shaft. BUT they wanted $480 to replace em!! So I'm taking it now to a local mech to replace the u-joints and rear bearing seal (leaking). They quoted me $180.
I'd happily pay $480 at this point if I knew it'd fix the vibration but I'm just hopeful at best... Crossing my fingers!

 

Hopefully they aren't just taking a shot in the dark. Did he give you any reason why he feels the u-joints are the problem?

Good Luck.

 

I was hoping not too. When I asked if he knew for sure that was the problem, he said "they are bad and this will for sure fix the vibration".
He had the truck up in the air and moved the tires back and forth and showed me where he could see play in the back joint. Also showed me the fluid leaking where the drive shaft hits the differential. He said it's the rear bearing seal out. The fluid leaking I could see for sure so that makes since. The play when moving the tires.... I'm no mechanic so to me it looked insignificant but he's the "pro" so I have to take his word for it I guess...?

He did say he put brand new stock size 2011 F150 wheels and tires on it at first and the vibration was still there. So that eliminates there being a wheel or tire problem.

 

Well guys I picked up my truck today from the local mech and it looks like the vibration is gone!! $69 for the dealership to diagnose the problem then $213 for my local shop to replace the rear bearing seal and the front and back u-joints on the main drive shaft and it seems to be finally gone! So weird that this started the instant I went to bigger tires?
Anyways, I hated to drop that $300 but at this point it's worth it!

Thanks for all y'alls help and input.