Vibration 70-80mph after balancing numerous times and getting an alignment

[Rockman5159]

Hi all, I have a 2021 F150 Limited with CCD and Adaptive Steering.

I have a bit over 36,000 miles on the clock. The truck used to have 35x12.5 tires and when I bought it with a leveling puck, it rode smooth and straight up to and past 80mph.

However, after a while there was a vibration that started which I assumed was the 35" tires chunking and wearing unevenly. So I bought new 295/70/18 Michelin Defenders (old tires were worn and balancing wasn't doing it so I figured it was due for a new set).

The truck still vibrates like crazy over 70mph+. It gets worse the faster I go. If I really pay attention I think a mild vibration starts at 55mph. Feels like the whole chassis is shaking and in return, the entire cab is shaking.

The truck has been balanced/road-forced numerous times at this point at different places and has gotten 3 alignments. The driveshaft looks good and I don't see any scoring on it so makes me think it's not the driveshaft problem everyone is having. Local shops have all said the other suspension components look fine.

We've been on the road for the last 6 months (25k+ miles) and for all of it, I've been facing this vibration. I'm in Southern Cali for this month and about to drive back home to VA and am not looking forward to this drive back.

Since we are constantly on the move I have had no luck having a dealer take a look at the vehicle. I haven't even been able to get the Limited badge that's falling off replaced. Now I am out of warranty and likely will be completely out of warranty by the time I reach home and have time to take it to a dealer.

Does anyone have any suggestions for shops around Los Angeles that can help or guide me to a Ford dealer in the area that will help?

Any suggestions on repairs?

As always I appreciate any and all help! Thanks!

Edit: truck has a spacer on the front shocks, Deaver +3hd leaves in the back with an airlift (currently aired all the way down unless loaded). Has a ranch hand grill, leer bed cap and I cut off the air dam that broke (in case anyone thinks these mods may cause the vibration).

Please let us know what you finf out what is causing the vibration. I have a 2021 which has a similar problem. It started around 6000 miles and seems to be getting worse. Mine starts around 60 65 mph. I ve switched tires and wheels Mine has a noisy drone when it vibrates,

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