2018 Dually Vibration

[TxRamzilla]

Picked up a 2018 Ram 3500 dually long bed with ~58k miles. The truck had brand-new wheels and tires installed before purchase. I noticed vibrations from both the front and rear, so I had all six tires road-force balanced. The front is now smooth, but I still have a significant rear-end vibration at ~75 mph, bad enough that I have to back out of it to maintain control. Wheels and tires are new, so I’m ruling out bent wheels. The truck is leveled.

Looking for guidance on where to go next. Current suspects:

• Rear driveshaft balance or excessive runout

• Incorrect pinion angle due to the leveling kit

• Dually-specific issues (inner/outer tire mismatch, improper indexing, spacer or hub mounting issues)

• Axle or hub runout

• Rear suspension/shock issues (overly stiff or worn shocks amplifying vibration)

• Rear wheel bearing or axle flange issues

Has anyone dealt with a similar high-speed vibration on a 4th-gen dually? Appreciate any insight before I start throwing parts at it.

 

[Ritchie_Rich]

Why were the wheels replaced?

 

[Hagar1]

Picked up a 2018 Ram 3500 dually long bed with ~58k miles. The truck had brand-new wheels and tires installed before purchase. I noticed vibrations from both the front and rear, so I had all six tires road-force balanced. The front is now smooth, but I still have a significant rear-end vibration at ~75 mph, bad enough that I have to back out of it to maintain control. Wheels and tires are new, so I’m ruling out bent wheels. The truck is leveled.

Looking for guidance on where to go next. Current suspects:

• Rear driveshaft balance or excessive runout

• Incorrect pinion angle due to the leveling kit

• Dually-specific issues (inner/outer tire mismatch, improper indexing, spacer or hub mounting issues)

• Axle or hub runout

• Rear suspension/shock issues (overly stiff or worn shocks amplifying vibration)

• Rear wheel bearing or axle flange issues

Has anyone dealt with a similar high-speed vibration on a 4th-gen dually? Appreciate any insight before I start throwing parts at it.

First thing that I would do is to try to determine the frequency. Is it engine speed, driveshaft speed or tire rotation speed. Each of these runs at different speeds so it will help narrow it down.
Pinion angle could cause a problem.
Is it a multi piece driveshaft? If it is multi, is it properly phased. If it is a multi piece, is the hangar bearing OK? If I recall correctly, there should be a master spline so that it goes together only one way but strange things do happen.
Is there a U joint on its way out?

 

[Hagar1]

Picked up a 2018 Ram 3500 dually long bed with ~58k miles. The truck had brand-new wheels and tires installed before purchase. I noticed vibrations from both the front and rear, so I had all six tires road-force balanced. The front is now smooth, but I still have a significant rear-end vibration at ~75 mph, bad enough that I have to back out of it to maintain control. Wheels and tires are new, so I’m ruling out bent wheels. The truck is leveled.

Looking for guidance on where to go next. Current suspects:

• Rear driveshaft balance or excessive runout

• Incorrect pinion angle due to the leveling kit

• Dually-specific issues (inner/outer tire mismatch, improper indexing, spacer or hub mounting issues)

• Axle or hub runout

• Rear suspension/shock issues (overly stiff or worn shocks amplifying vibration)

• Rear wheel bearing or axle flange issues

Has anyone dealt with a similar high-speed vibration on a 4th-gen dually? Appreciate any insight before I start throwing parts at it.

One more thing ... just because the tires are new, doesn't rule out bad tires. I once was involved in solving a vibration and it turned out to be tire. They were brand, spankin' new. Let the air out, you could see the tire distort and when we broke them off the wheels, they darn near tied themselves into a knot.