Weird shaking on my 2012 670 D13

!st things 1st always change FUEL FILTERS, then start with any CK. eng lights,CK. the drive/line (u joints) if greased at any time between oil changes,The ride High can make for funny vibs. sometimes, when all fails take it to the shop that made the eng. not truck dealer to have inject. CK for cut/out that might make at vibrate at times?

 

Next the center rubber drive/shaft hanger 1/2 way down drive shaft, Air cleaner all mant. done at shop will tell them to look for prob. while doing it?

 

Hi sash, generally, a vibration in the seat is a drive line problem.Lug nuts tight? U-joints are weird, and not terribly expensive. I'd start with new U-joints. The only other thing I can think of is a bearing somewhere, since the truck isn't that old, I'd focus on the trans. Good luck.

 

I would start with a three axle alignment, you might have bad king bin.

 

Another thing, check all the mounts, although the truck isn't that old. One thing a friend had a 379 Pete w/Cat motor, had a similar vibration, tried everything, finally an old timer mechanic said, check your harmonic balancer( big pulley at front of engine). Sure enough, replaced it, and fixed the problem.

 

Kingpins are on the steer axle, but I doubt that, your truck isn't that old. That throttle and putting into neutral thing just seems like drive line.I know, makes for a long day. Like I say, U-joints are weird, there may not be any slop when you grab the driveshaft, but when you take them apart, you'll see the "galling"( little dents where the bearings ride)and u-joints take most of the shock. Good luck.