Nexus Chassis noise

[Ellen_Higgins]

I have a 2020 Nexus Viper 27V on 2019 Ford E450 chassis. There is a vibration noise coming from underneath the chassis, it is not in the engine. The vibration noise is only heard between 60 and 65 MPH. Below 60 and above 65 no vibration noise. Any suggestions as to what might be the cause?

[klutchdust]

Grit dog wrote:
Good luck getting it fixed.
If you have more detail on the noise like when it started, what it sounds like, if it’s present when coasting or in neutral, worse when accelerating or going uphill.
You said it’s mostly a noise but common issue would be an out of balance tire. It’s one of the few vibrations or issues that are speed sensitive only.

" It’s one of the few vibrations or issues that are speed sensitive only. "

Bearings are speed sensitive, bushings are speed sensitive and unbalanced or mis-balanced drive trains are speed sensitive. Rear end gears are speed sensitive, shall I continue.......

[Grit_dog]

Good luck getting it fixed.
If you have more detail on the noise like when it started, what it sounds like, if it’s present when coasting or in neutral, worse when accelerating or going uphill.
You said it’s mostly a noise but common issue would be an out of balance tire. It’s one of the few vibrations or issues that are speed sensitive only.

[klutchdust]

Ellen Higgins wrote:
Thank you to all the great comments and suggestions. Finding a Ford dealer that has a lift in their shop large enough for an RV is difficult. I finally found one, almost 100 miles from where I live and have made an appointment.

Shops that do truck wheel alignment are also possibilities. The dealer most likely will blame it on the rv builder and the rv builder on the chassis builder. Welcome to the life of the rv'er.

[Ellen_Higgins]

Thank you to all the great comments and suggestions. Finding a Ford dealer that has a lift in their shop large enough for an RV is difficult. I finally found one, almost 100 miles from where I live and have made an appointment.

[Ellen_Higgins]

To bobndot, it is mostly a noise, with a little vibration

[bobndot]

Take it to a tire shop. I would think that inspecting tires would be the easiest and cheapest thing to do. Maybe swap the front tires with the rear tires and drive it to see if that helps.
I once had a tire that could not be balanced, it was a bad tire and had to be replaced. Try to eliminate a tire problem first.

[docsouce]

If you have a chance look up "65 MPH Drone and loud banging in cabover curved panel" on google. This post from the Jayco Owners Forum might be of some help to you. It offers some very useful information on the possible cause of this. It did help me to eliminate this annoying issue on my 2020 Jayco 26XD class C. The second half concerning the banging of course doesn't apply here. Read it through, it bounces around a bit.

[klutchdust]

Don't forget the tail shaft of the transmission. Most likely drive shaft. Rarely do carrier bearings and universal joints fail on that new of a vehicle, but it is possible.

[ron_dittmer]

DrewE mentions this and I support his comment. I have read a rare few complaints over the years where modifying (stretching) the wheel base effecting the length of the drive shaft was the culprit. The change in length of the drive-shaft requires it to be rebalanced. The "Ford approved" company that modified the wheel base either over-looked or improperly balanced the drive shaft. Some drive shafts get quite long and segmented, making them very sensitive to being out of balance. If not balanced right, vibration and/or other strange noises are generated. One thing certain, you do NOT want to ignore it.

[bobndot]

Is it a vibration or a noise or both ?

[DrewE]

A few possibilities exist; offhand, and approximately in order of my guessed likelihood, it might be:
1. Universal joint/carrier bearing/drive shaft balance issues.
2. Out of balance or out of round tires/wheels.
3. A whiney sound, particularly one that varies with load, could be noise from the differential.

[Tyler0215]

Get up to speed when vibration starts, shift into neutral and see if the vibration goes away. If it does have the U joints and carrier bearings checked.