Thumping Noise

[HRENDEAVOR40]

Hello all, I have had this ongoing issue with a random thumping noise which seems to become more pronounced when the front suspension is loaded more (engine brake etc). No one can seem to figure out what it is and it has been years. It happens at all speeds and does not change when braking.

2004 Holiday Rambler Endeavor 40’ (RR8R). 
 

https://youtube.com/shorts/jJjx5Qw_who?feature=share

the video has the sound of the issue. 

[klcdenver]

I believe it is coming from your monitor for the rear view camera. It also has a microphone in the rear so you can listen to the engine etc…. It has a volume knob on it, try turning it down to see if your noise goes away. 

[HRENDEAVOR40]

Monitor sound was not on. It is a mechanical sound, not electrical 

[RBRODDER]

Does the frequency change with speed, assuming that it is a "in motion only" noise?

[HRENDEAVOR40]

Yes, as I go faster the more repetitions I hear. 

[Benjamin]

I'd inspect the front tires, like this:    https://www.rvtiresafety.net/2014/08/how-do-i-inspect-my-tires.html

the spin test could show certain issues with the axle also. I'd like to get a camera mounted under the RV to watch the tires as they roll, I suspect that would be useful, but only for the passenger!

[jacwjames]

33 minutes ago, Benjamin said:

I'd inspect the front tires, like this:    https://www.rvtiresafety.net/2014/08/how-do-i-inspect-my-tires.html

the spin test could show certain issues with the axle also. I'd like to get a camera mounted under the RV to watch the tires as they roll, I suspect that would be useful, but only for the passenger!

I had something similar happen to a Class C I had.  We were on a trip and I stopped and inspected the passenger side tire thinking that is where the thumping was coming from, didn't find anything.  It started to get worse and turned into a vibration and I stopped several times and never could see anything.  At some point he front shock failed, yup ruptured.   So we found a shop that could replace the shock and when they took the tire off the problem was evident.  A cord broke in the center of the tread with a pronounced bulge in the tire.  I never saw it during the inspections, I must have stopped with the bulge on the bottom every time. 

Just by chance I had two other tires fail on the same trip, they were the Firestone tire during the time they had tread separation problems.  We actually had one tire where the tread was completely peeled off.  We were in the middle of S C headed toward Charleston and finally found a decent tire shop with 6 new tires and had them all replaced. 

 

One other possibility is look at your wheel well trim.  It is held in place with some screws.  We had one of the screws come out causing a thumping should driving down the road but it was a random thumping. 

[Martinvz]

We recently had a similar issue on our Honda CR-V. We replaced the tires on the toad 2 years ago and from the get go had issues with the noise and a thumping sound. Last year we had the tires checked and apart from rebalancing and alignment they were declared to be fine. However the noise got worse. Then in December just before heading south a periodic shaking started happening. 
I took the car to a tire shop and on inspection there was runout on all 4 tires and one tire was really bad. All 4 tires were replaced and balanced. This helped considerably and the thumping noise was gone. However the shaking still periodically showed up. I the. Took the car to a shop and they checked it out and recommended replacing the struts on all 4 corners. With 80,000 miles on the odometer and about 20,000 miles towing, I accepted that as being beyond their normal life.

We become used to the noises from our vehicles (especially our daily drives) and do not always get the appropriate maintenance advice when we ask for it.
Just my experience in this case.

How to find a the throwout: place the suspect tire on a spin balancer and look for the uneven rotation of the tread. Some spin balancers have an idle wheel that can measure the throwout for passenger vehicle tires but this may not be available for heavy duty tires.  See the attached video

Edited May 18 by Martinvz
Added additional info and video

[RBRODDER]

9 hours ago, HRENDEAVOR40 said:

Yes, as I go faster the more repetitions I hear. 

Definitely inspect the tires first. 

[Larry Laursen]

Check the fender mounting brackets in the wheel well.  There are metal brackets that come out to hold the fiberglass fenders.  The screws will rust and they come loose tapping the bracket.  Pull on the fenders and see if they can be moved.  Then reattach them with new screws.

[Michael Powell]

Look at the ring and pinion gear mene had this and had to put a 3rd member That fixed it... not cheap...

[Baldfuzzz]

 Had a similar thumping noise that vibrated through the MH.  The shop found the problem after they dropped the drive shaft. It was ring and pinion gear. Several teeth broke off. 

[DZZippy]

9 hours ago, Michael Powell said:

Look at the ring and pinion gear mene had this and had to put a 3rd member That fixed it... not cheap...

 

3 hours ago, Baldfuzzz said:

 Had a similar thumping noise that vibrated through the MH.  The shop found the problem after they dropped the drive shaft. It was ring and pinion gear. Several teeth broke off. 

I’m following this one a bit closely. I do not have a thumping sound though. Just curious……. Did either of you have a substantial vibration change at all when trans was shifting gears? I’m starting to pick up a slight constant vibration at all speeds myself (increasing with speed). I have a noticeable pronounced vibration change that is worse when shifting from 3rd to 4th and goes back to a slight vibration after picking up more speed in 4th. The other gear shifting appears to just have a constant vibration throughout. Sometimes I can even see the speedometer needle briefly bouncing when this occurs going into 4th.  U joints are good. Driveshaft is phased but need to make sure the balance weights are still present. Seems like I may have a bit excessive slop in the pinion gear but need to look up the spec for backlash etc.

[Tom Cherry]

ONE CAUSE….been there….done that.

IF you have the EYE & STUD style shock mounts….maybe the issue.  The “eye” is a ring or lower mount with a steel bushing inside a rubber donut…bolt goes through

Stud is the top.  A threaded stud with a “flat” on the top.  Lower curved washer…rubber donut…then into the mount….donut and curved washer….there is a steel bushing running down.  You tighten or torque the too stud nut until you can’t turn it…and it compresses the rubber donuts 

if the nut backs off….banging….also has been known to damage the shocks (Source told me that).

the “approved” method is to pull down the boot.  Use small Vice Grips right under the mount….the shock never travels that high.  Use a ratcheting short box wrench.  Not the lever….the flip over.  Tighten as much as you can as your “hand” will be limited to the contortions of the upper mount.

MAYBE?  Mine have 60 K…have been tightened once.  One on each side.

Good luck"

[HRENDEAVOR40]

Thanks for the replies everyone. It ended up being a wheel bearing. When it was cold it would have zero play. I drove it for 15 minutes and immediately jacked it up and felt play in the wheel. 

[zmotorsports]

9 minutes ago, HRENDEAVOR40 said:

Thanks for the replies everyone. It ended up being a wheel bearing. When it was cold it would have zero play. I drove it for 15 minutes and immediately jacked it up and felt play in the wheel. 

 

Personally, I have not seen a wheel bearing create a "thumping" noise, usually they are more of a growling and rough when they go bad.

 

Are you saying there was axial play or radial play?  

 

A wheel bearing should not have any radial play but there should be some axial play or clearance.  Specification is .001"-.005" of axial clearance when the bearings are installed and the final torque applied to the axle nuts.