Rear end thump, what to do.

Topic: Rear end thump, what to do. (Read 1508 times) previous topic - next topic

Re: Rear end thump, what to do.

Reply #25 – April 10, 2023, 08:46:36 am

Another diagnostic/repair option would be a visit to American Shifty co. in North Little Rock. Others have had driveline issues addressed there, including the dampener and been pleased with the service. . Its kinda on your way home.

Re: Rear end thump, what to do.

Reply #26 – April 10, 2023, 05:56:49 pm

I had a very heavy thumping noise on my 95 U320 when I would accelerate hard, then brake, then accelerate again.
I found it to be the rear bulkhead had enough play from the bolts rusting out that it was slapping and pounding the rear angle iron.

I cleaned it, cut away the fiberglass belly about a foot in front and cleaned out the rust, painted, and drilled through for new SS bolts . End of problem.

Check your FRONT and REAR bulkheads. If you see some cracking in the side wall of the coach down around where the bulkheads are, you might see the problem if that is YOUR problem.

Re: Rear end thump, what to do.

Reply #27 – April 10, 2023, 08:24:04 pm

A bad or loose shock can make a crazy knocking sound too.

Re: Rear end thump, what to do.

Reply #28 – April 10, 2023, 08:29:19 pm

Quote from: golfnut – April 09, 2023, 12:09:31 pm

Hello forum members, I have been doing pretty good keeping Jor's old 34' going down the road. This is out of my knowledge though. I will post pics, I think I have that part figured out. We are at Enid Lake Mississippi. Very nice Corps. campground. Yesterday driving we started hearing some thunking, I just thought something was rolling around thumping in a cabinet. It got worse, wife says coming from underneath. It does seem to thump letting up, and then pressing down throttle pedal. Which I would imagine, could be what I am seeing in pics.
We were headed to Biloxi, but thinking at the every least we should head back towards home, which is about 600 miles to Missouri. Any knowledge and help would be much appreciated. Kim and Elana McCoy

Mine did that. Thought it was u joint. Sounded like running on rumble strip but not quite as loud. Turns out slide pin seized on passenger rear disc brake. Melted disc and rotor. Only noise when letting off and accelerating. No fun. Expensive lessons

Re: Rear end thump, what to do.

Reply #29 – April 11, 2023, 07:36:57 am

Kim,

Suspect you have concluded from the number of different things that can cause your noise that you HAVE TO determine the cause before driving very far.

Transmission and rear axle are the same (though in "backwards") as many trucks. The air disk brakes are found on many fire trucks. So, you should be able to find a HD truck mechanic to give it a quick look "under" to rule in/out the root cause.

Re: Rear end thump, what to do.

Reply #30 – April 11, 2023, 08:46:29 am

Good morning, we went to tractor supply in Batesville. Bought a lock n load grease gun, which is nice. Hit the drive shaft and u joints, no change in noise. Elana has termed it knocking, and says it sounds like it is coming from below floor in front of fridge. I have checked bulkheads everything looks good, has been repaired. Nothing that I can see with brakes. We are getting some oil around rear wheel outside dually (axle seal?) I have a shop near home, that I trust, would like to get there. Thanks

Re: Rear end thump, what to do.

Reply #31 – April 11, 2023, 08:47:44 am

Also checked shock bolts all good.

Re: Rear end thump, what to do.

Reply #32 – April 11, 2023, 09:15:16 am

Dose the knock increase with RPM and /or road speed,any chance of recording sound and sending it to one of our phones.

Re: Rear end thump, what to do.

Reply #33 – April 11, 2023, 09:16:05 am

It seems to be more of a suspension problem then driveline, but who knows. Kim

Re: Rear end thump, what to do.

Reply #34 – April 11, 2023, 09:19:10 am

That's funny, I was telling Elana around the campfire last night, that we should make a recording. Post it and call it Name the Thump.

Re: Rear end thump, what to do.

Reply #35 – April 11, 2023, 09:30:12 am

It doesn't do it shifting gears, or downshifting, or retarder use or braking. It will knock more like, in just the movement of slowing or increasing speed. Honestly, to me it sounds more like an old house settling on its foundation.

Re: Rear end thump, what to do.

Reply #36 – April 11, 2023, 10:47:15 am

Could be one of your torque rods bolt broke but unlikely,you can take a pry bar or big pipe wrench and wiggle/push to see if any play,you have 5 rods in back and 5 in front,rubber bushings could be shot,redid all mine years ago,it's a labor intensive job.

Re: Rear end thump, what to do.

Reply #37 – April 11, 2023, 12:12:38 pm

"Elana has termed it knocking, and says it sounds like it is coming from below floor in front of fridge"

Are you sure your bowling ball didn't come out of its carry bag down in the basement? 😆🤣

But on a serious note, could it be something loose down in the basement?

Re: Rear end thump, what to do.

Reply #38 – April 11, 2023, 04:30:43 pm

My vote goes to a shock bolt not tight enough and it is moving in the mounting brackets. We had that and one in rear just needed to be tighter. Problem solved.
Johnh

Re: Rear end thump, what to do.

Reply #39 – April 11, 2023, 07:09:40 pm

Looks like you still have the original Bilstien shocks,consider upgrading to Koni FSD,will be a world of ride improvement.

Re: Rear end thump, what to do.

Reply #40 – April 11, 2023, 10:50:07 pm

Quote from: golfnut – April 11, 2023, 09:16:05 am

It seems to be more of a suspension problem then driveline, but who knows. Kim

Shocks, shock bushings and mounts, torque links and bushings
Scott

Re: Rear end thump, what to do.

Reply #41 – April 12, 2023, 07:39:08 am

Quote from: golfnut – April 11, 2023, 09:30:12 am

It doesn't do it shifting gears, or downshifting, or retarder use or braking. It will knock more like, in just the movement of slowing or increasing speed. Honestly, to me it sounds more like an old house settling on its foundation.

At the end of the day, all you can do until you have the time to put your coach up on jack stands and have trained hands, eyes, ears, and mind do a thorough inspection is track the rate of change. Is the noise getting better or worse? How quickly is the noise changing. If it's the same mile after mile, from everything you've described, don't worry. If the noise is getting worse, and you're out on the road find a friendly truck shop, show them how to block your suspension for safety and ask them to remove the rear wheels and do a thorough inspection for anything that might be awry. Do ask them to keep the rear level as they raise it and place it on jack stands. Or, just stop worrying and have a good time.

Re: Rear end thump, what to do.

Reply #42 – April 12, 2023, 09:50:53 am

Thanks to everyone, great to have all the response. Same noise, no worse or better. 300 miles to the homestead, so just headed down the road. Jor had the front shocks replaced, backs are original. Would be nice if that is the issue, I have checked bolts, but haven't put any tourque to them. We have still had a great time, the weather the last few days has been sunny and in the 70's. We did lose a hub cap somewhere yesterday, I normally give them a little push before heading out, but failed in doing that. I of course will update everyone when I know more. I am pretty sure I didn't bring Ernie (my bowling ball) along for the ride.
Kim McCoy, I see we have a Hatfield on the forum, no feuding from this McCoy.

Re: Rear end thump, what to do.

Reply #43 – April 12, 2023, 10:26:13 am

You also have the Real McCoy.

Re: Rear end thump, what to do.

Reply #44 – April 12, 2023, 10:31:26 am

In our travels I was always the one noting and describing odd noises. Jeff is too hard of hearing to be able to accurately place the location of things. In our '02, we had two occasions of noise. Once it was a shock mount that needed to be tightened and the other was something loose on the tag axel. Both times I got a very discrete eyeball from the tech at Foretravel (but they loved me because we always brought boxes of donuts or bought pizzas for the entire shop during our stays), but then they had to admit that they had found something that cured the phantom noise.

Re: Rear end thump, what to do.

Reply #45 – April 12, 2023, 01:42:54 pm

What was the noise on the tag? My air brake cans rattle just wondering if that is what they found an how they fixed it.
Thanks, Larry

Re: Rear end thump, what to do.

Reply #46 – April 13, 2023, 11:19:05 am

Quote from: Townrestor – April 12, 2023, 01:42:54 pm

What was the noise on the tag? My air brake cans rattle just wondering if that is what they found an how they fixed it.
Thanks, Larry

This was quite a while ago and I really cannot remember. Whenever we went over any bit of rough road surface something would bang underneath the coach. I knew it had not always sounded like that, so I asked them to look. They may have taken it out for a drive to help diagnose.

Re: Rear end thump, what to do.

Reply #47 – April 15, 2023, 12:00:54 pm

We made it home safe and sound. I have Shorty up on stands, I should get underneath today to check things out. Thanks

Re: Rear end thump, what to do.

Reply #48 – April 16, 2023, 05:40:14 pm

I have found 2 rear shocks, both being forward of rear tires, that are not right. I will post pics, the driver side shock bottom mount I can wiggle, the big washer I can turn freely. The other side, you can see busted metal piece. I will have all 4 rear shocks replaced as they are original. So,I replace them with the exact ones as Jor put on the front? What do I need to know about the ride height adjusters after new shocks put on. You all think this is enough of an issue to cause the clunking? Thanks again. Kim

Re: Rear end thump, what to do.

Reply #49 – April 16, 2023, 05:46:37 pm

That thing that is broken will need to be rewelded and new shocks won't change the ride height.

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