I was thinking high head pressure causing extra load making it vibrate. Try washing out the condenser coils. Good luck
2004 Ford F250 Super Duty 6.0 Diesel, Bilstein 4600 Shocks, 16K B&W Patriot, Michelin M&S
2014 Augusta Flex AF34RS Trailair Tri Glide pinbox,
JT Strong Arms , Bridgestone R250'S, KYB Monotube Gas shocks
Finally a smooth ride !!!