I searched about the symptoms my 06 ram 3500 was having and found a lot of threads on different forums about vibrations, but nobody seems to follow up with what the fix was. The threads just kind of stop with no conclusion, so I thought I would post what fixes I did to my truck in case anyone is trying to search this out.
Ram 3500 dual rear wheel 2wd, cummins diesel automatic, 430,000 km's used a work truck, it always has 2000lbs in the bed.
Pulling a trailer home, engine started to make loud knocking noise and blowing smoke like a steam locomotive.
Found #6 injector stuck open( it was the only injector that was wet, clean with no carbon on it), replaced all 6 with injectors from GB manufacturing.
Drove truck for a month with new injectors, at idle the steering wheel was shaking badly intermittently. Stop at red light, shakes, next light no shake. Truck starts instantly, fuel rail pressures check out, but power feels lower. Borrowed scan tool and did cylinder contribution test, had 2 cylinders below 89%, and one above 110%. Changed the 2 low injectors, the 2 low now were at 99 and 98. The high injector dropped to 104. Contacted injector manufacturer, got email denying it had anything to do with their injectors, strangely now the idle is perfectly smooth after changing out #2 and #5 and truck has grunt again.
Now that my mind is looking at the truck more and the rough idle is gone, I notice I get low speed rumble at 60 km/h and then a resonance at 100-110 km/hr. Then the truck goes smooth at 120 km/hr.
Winter is here, so I put on 6 new tires on the truck. On the ride home , I notice my 60 km/hr rumble is completely gone, new tires do make a difference, even though my old set were rebalanced recently.
Get up to speed, notice the resonance now seems worse since the tire change, maybe some of the tire vibes were cancelling something else out. Check the u joints, all are tight, steady bearing is good. Finally drop driveshaft off at driveline shop, found the 2 piece shaft had not only gone out of balance, but was bent. Got shaft straightened and balanced, truck feels like its brand new again.
Never trust new parts to not be defective, and don't think its just one part that is bad.