Noise under the car

[Unimog 406]

Broken spring, I recall hearing of this some time back
Good luck Graham

 

[Tom109]

I've experienced a similar deep knocking noise when driving over uneven soft sand. Have not heard it in a road driving environment.

I’ve heard/felt it on soft sand as well. I thinking the driveshafts

Same, last weekend 3 hours of sand tracks and same knocking. Strange for soft terrain.

 

[Logsplitter]

Have you checked the tie rod. Does it twist easily. My did and used to clunk on one of the swivel joints when articulating off-road. It’s fixed now but don’t know what the dealer did to fix. If you have diff guards make sure they are not interfering with the steering damper when fully loaded or max articulation

 

[Wueste]

I have an appointment at a local garage on Monday. Then I'll have a look under the car. I also have an underbody protection from Rival, maybe the noises come from something hitting or rubbing against it.
I will report back to you.

 

[Wueste]

I’m back from the workshop, and I’m thrilled to report that everything’s in order!
No loose cables, no worn joints, nothing amiss under the hood. During the test drive I could hear the noise with the mechanic, but everything is solid and in order under the car.

One cool thing about the workshop is that they have a lift with vibrating plates for the front and rear axles. This allowed us to test everything thoroughly.

He says: „Don’t worry, I’ll definitely make it to Germany. A solid car.“

Once I’m back home, I’ll do a more in-depth check-up.

If you or someone you know is having issues with their car in the Sardinia, Costa Rei / Castiadas area, I highly recommend Centro Revisioni Castiadas. They’re super knowledgeable, friendly, and they’ll do their best to troubleshoot any problems, even if there’s a language barrier.

Centro Revisioni Castiadas

Now I'm going back to the sea,
greetings wueste

 

[Born_ in_a_tent]

Check whether you have a bolt missing from the underside of your trailer hitch. If the bolt is missing the hitch can rattle in the receiver causing a clunking sound.

 

[Ron50]

Today I had my weekly special intimate moment with the Grenny, with other words I routinely check the car.

When I did the transfer case seal check I noticed that a cable had been rubbing on the front cardan shaft from transfer case to front axle...

Tried some zip tie magic to hold it a little away from the shaft for now, could this be the noise we where having...
View attachment 7894194View attachment 7894195

I just packed the cable away from the shaft flange with foam. Noise gone.

 

[Cradle]

We have the same kind of noise since the QM its first decent muddy offroad trip...

We will try to film it this week to show our dealership.
Did check all the bolts on the front axle myself just to be sure everything OK.

Is the issue resolved yet? I have been doing some heavy offroad, the clunk noise is now coming out. It is coming out when the vehicle is going on uneven sections of the track.

 

[HereinDaRockies]

Hi guys, just a quick update again: I figured out exactly when the knocks down below occur: it doesn't occur when going over speed humps on level ground or downhill, because then the vehicle basically "coasts" over the bumps. When I go over a speed bump at a slight uphill, and I give it a bit of speed so that it coasts over the bump, there's no knocks. When I go over the same speed bump, but slower, so that the drivetrain has to work, then you can clearly feel the clunks/knocks, and whole family agrees, especially sitting on the rear seats. So it can't be suspension related, but rather drivetrain related, because it only clunks when the drivetrain is under torque. So it has to be either the drive shafts, or inside the transfer case. I checked the t/c mounting, hoping it might be cracked and moving around, but that also seems to be fine...
I'm now just driving it and waiting to take it in at the 30k service where I will demonstrate to the mechanic what's happening...
Surely this can't be normal...
Cheers

Same here When I go over certain bumps in D, it makes a thud. When going over the same in neutral, no thud