Troubleshooting help: Noise when backing up (1 Viewer)

[Bighead]

Trying to track down a noise and am hoping someone can help me out with some troubleshooting. Current mods are in my sig line.

While backing up I will hear a fairly loud pop or clank noise usually after rolling about 4 or 5 feet. It sounds metal on metal. This only happens once and only when I have been parked for a bit. The loudest is usually when it has been parked overnight but I can also occasionally hear it after a shorter stop. The first time I heard it was while backing out of my garage and thought it was the garage door spring making noise.

Last service was done at the local dealership and was an oil change. They had it in for the seat belt recall and a software update so I figured why not. Other than this noise everything is fine.

Any thoughts?

 

[Sandroad]

One member zip tied his phone underneath and got a video of what was causing rear suspension noise. Would that help in your case? You might be able to quickly see the movement in the springs/links/etc causing the clank.

 

[bloc]

Trying to track down a noise and am hoping someone can help me out with some troubleshooting. Current mods are in my sig line.

While backing up I will hear a fairly loud pop or clank noise usually after rolling about 4 or 5 feet. It sounds metal on metal. This only happens once and only when I have been parked for a bit. The loudest is usually when it has been parked overnight but I can also occasionally hear it after a shorter stop. The first time I heard it was while backing out of my garage and thought it was the garage door spring making noise.

Last service was done at the local dealership and was an oil change. They had it in for the seat belt recall and a software update so I figured why not. Other than this noise everything is fine.

Any thoughts?

Does having the steering wheel straight or turned have any impact on the noise?

 

[Bighead]

Does having the steering wheel straight or turned have any impact on the noise?

The steering wheel is usually straight when it happens. I haven’t had it parked long enough in one spot with the space to crank the wheel too much when backing out.

One thing I forgot to mention is that I have felt a mild thump through the floorboard in sync with the noise.

 

[Bighead]

Had my wife record the noise. It does look like it might be related to the rear suspension since the noise occurs when the rear tires drop off the lip near the garage door.

 

[bloc]

Check your sway bar links, upper and lower shock mounts.

 

[4gotalot]

I think you have, "the clunk". The clunk relates to to rear shock, top bushing and washer assembly. A quick description is that the rubber bushing are to soft and or there is not enough pressure on them to keep the pilot washer or hat washer in place. As your shocks extend and retract, the pilot washer comes out of the frame and "clunks" back in.

That video was perfect. Have a great Thanksgiving!

 

[Sandroad]

I vote shock mount, based on the noise and when it occurs. See if your wife can isolate to L/R. It may be tough to find with the suspension under load. Would jacking it up help to get the noise/movement to occur?

 

[nwfl4runner]

easiest would be to crawl underneath and try tightening the shock nuts.

 

[4gotalot]

I did a bunch of trouble shooting on the shock mount clunk a few years back. There was a speed bump in a parking lot close buy that I could repeat the noise. I even disconnected the rear shocks and tied them out of the way and the clunk went away. The ride without the shocks attached was kinda like a carnival ride.

Crawl under there and reach up and grab the top section of the shock as close to the top as possible and give it a pull down and back forth like you were trying to shake an opossum out of a small tree. Just no snarling teeth or hissing.

If it is the top bushing assy, then a quick temporary fix can be done by removing the nut on top and installing another shock washer with the same I.D. hole size on top then tightening the nut to its stop and torque. This just smooshes the bushings about an 1/8" more and increases the tension to keep the assy in place. Just make sure the top washers stay centered and end up on the larger diameter, unthreaded portion of the shaft so the nut can be torqued. Also anti seize is highly recommended in that location because those nuts are self locking by means of out of round and are best if not used again. Call ARB for new bushing and self locking nuts. They know about "the clunk".

EDIT: Check to make sure you do not have 2 hat washers installed, 1 above and 1 below the frame before adding to the washer stack. The OEM washer stack only uses 1 hat washer under the frame keeping the assembly centered on the shaft and kept in place by the pressure from the rubber bushings. Thank you, Taco2Cruiser for reminding me about the possible use of 2 hat washers from ARB.

 

[Bighead]

I have a big road trip next week and wanted to make sure it’s not something that would be a safety issue. I’ll be under the cruiser tomorrow tracking this down.

Thanks everyone for the ideas and help.

 

[Bighead]

Quick update: Did a quick look at the rear suspension and did not see anything loose or out of the ordinary. The upper shock mounts appeared to be okay but I need to put it on stands and pull the tire so I can get a better look. Little difficult to do a proper job since most of my tools are packed for the move back to CO next week.

I did notice today that the noise still happens before dropping off the garage lip in my Youtube vid and also occurs while backing and turning though the sound wasn’t as pronounced.

Each time it happens I am applying some brake pressure, it is only while in reverse and happens whether going straight or turning.

Any new thoughts? Brake related? Could it be something up front?

 

[bloc]

Rear caliper bracket bolts? Should be easy to check those.

 

[Fishinsea]

Keep us updated please.

 

[psnyman]

Keep us updated please.

Can the OP provide the post Morten on this assuming it got resolved?