Rear rumbling & vibrations at hwy speed – Intermittent, getting more frequent

[KTBaillif]

Rear rumbling and vibrations at highway speed – Intermittent, getting more frequent.


1999 Safari Zanzibar, Magnum Chassis, Diesel Pusher – The rumbling sound and vibrations in the rear are the same as when traveling over rumble strips. Previously, thought it was the road surface but now it is happening more frequently regardless of the road surface.



Please help identify this problem.

[BFlinn181]

Does the noise change when you push on the gas pedal or let up and coast? It could be a number of things, the cheapest would be U joints in the drive shaft, more expensive would be bad differential.

[jeryan59]

Has something changed on your ride height? I have found if the ride height changes it will affect the u-joint on drive line and will get a rumbling vibration. Another thing that can cause this from my experience is an air bag problem, which can change the ride height (realizing some may not have air bags).

[jacwjames]

As previously mentioned the likely culprit is a U-Joint. Have they been lubricated lately, I lube mine +2 times per year. I would inspect to see if you can see evidence of failure. Make sure the bolts are tight and that there isn't any play in any of the caps.

I just bought a spare set of U-joints for my rig, cost was ~$120. I have +100K on my rig so I will be inspecting more frequently.

[Ray,IN]

Originally Posted by jeryan59

Has something changed on your ride height? I have found if the ride height changes it will affect the u-joint on drive line and will get a rumbling vibration. Another thing that can cause this from my experience is an air bag problem, which can change the ride height (realizing some may not have air bags).

That happened to my MH. First the rumbling and vibration at 60 MPH, then at 35 MPH, then at 20 the rear of the coach began jumping up and down. I limped to a Petro truck stop, asked their service shop to look at it, they found the rear ride-height rod had a broken rubber end piece. One hour later and $90, I was on the road again.

[twinboat]

Did you check the wheel lug nuts?

[slickest1]

If it not U joints or a driveline problem, and the wheel nuts are ok, another thing that can be suspect is a inner rear wheel that is cracked between the bolt holes and is getting worse. The only way to check that is remove outer wheels.
You may also have a wheel bearing going bad.

[Papa_Jim]

Keith,

I'm pretty sure by your description of things that you have a U joint or U Joints gone in your driveshaft.

With the severity of the symptoms that you are describing, I think you should immediately, if not sooner, find a truck shop that can work on your rig.

You don't want to experience the problems that are possible with a driveshaft failure on the road, from severe transmission damage to a bad accident on the road.

Jim

[GaryR.]

Keith, Check your "ride-height" first. I had the same exact thing happen as RAY,IN and it was on a 2000 Harney Coach with a Magnum Chassie. The rubber piece on the ride-height adjusting rod some how tore in half and I had a terrible viberation and the knife and fork drawer even came out and fell on the floor. Good Luck Gary

[Ray,IN]

You can make a determination if it is the ride-height linkage. Simply measure the height of your trailer hitch with air dumped, then after the building air pressure, the governor makes the Pshsssht sound/reached set pressure. if the measurement is close to the same, you found the cause of your problem.

[KTBaillif]

Thank you all for your help with this problem. It did turn out to be the rear airbags. Because they were leaking, it put a strain on the U-Joints. We are having the airbags replaced and the U-Joints checked out.

[Papa_Jim]

Glad to hear that you got things sorted out.

Happy trails.

Jim