Rear Thumping noise

[DEACONBOB]

My new Legacy has a thumping noise coming from the rear as I go over bumpy sections of the road. I took everything out of the trunk and it's still there. Took the car to the dealer and they did not find anything. This noise is driving me crazy!!! My son has the same car and no noise!

[Perscitus]

Check under the trunk liner - maybe the spare or tools in there are loose. Also release and re-set both of your back seats. Make sure they click into place. Try that first. Then move on to suspension (rear sway, bushings, end-links, struts). 2010 or 2013, you never know. Good luck.

[bsevic]

Have a similar noise (I wouldn't call it thumping, seems to be more metallic based) and seems to coming from the rear passager side. I've taken the spare tire out and tighten everything back up (no help). I do have the 19mm rear sway bar installed, but I'm not ready to declare it that. To me it seems to be from the seat latches but even with the seats down I still have the sound. It seems to resonate when transitioning the vehicle into a turn. I agree its something that drives crazy.

[GTEASER]

Could be a broken or loose sway bar end link if it happens when transitioning into turns. Check the upper strut mounts and shock mounts to make sure they are tight.

[hmmrdwn]

I had a rolling sound in the back of a Ford one time. It drove me crazy. I searched the trunk, rear package tray and wells behind the rear wheels. Took it to the dealer and they drove around their parking lot with a service tech in the back seat. The tech pulled the seat up and found a metal rod that was in there from production. The rod rolled back and forth when cornering in a stamping indentation. Glad they found that!!!!

[Jace2010LGT]

Check the rear strut mounts. Make sure the bolts are tight. Do not remove them. Next bounce the car while you check for popping from the mount. I suspect blown strut mounts.

[GTEASER]

Blown strut mounts on a brand new car? I vote for just loose.

[SurlyOldManMN]

Blown strut mounts on a brand new car? I vote for just loose.

 

While certainly more likely... there have been a small handful of folks who had leaky struts warrantied out. It wouldn't be that surprising.

[minuccims]

trunk monkey?

 

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[DeltaSniper]

Exhaust banging against the bumper?

[Jace2010LGT]

Blown strut mounts on a brand new car? I vote for just loose.

 

Sorry, I missed the new car part.

 

To OP is it a contact type noise like something smacking the bottom of the car?

A thump noise that happens when the suspension hits an impact or imperfection in the road? Clacking noise when going over bumps? Does it change with weight/passengers in the back? I may be able to help if you can answer these questions. If all else fails ask for a test ride with a tech. Once he hears it he will know where to go. The best time is in the afternoon because in the morning they get busy and after lunch most places slow down. I work as a tech and if you can get it to do it with him in the car he can find it and fix it. Maybe just ask to talk to the tech. You would be surprised how many times I get tickets that read "customer states noise at highway speeds check and advise". What am I supposed to do with that? Is it wind noise, rattle, vibration? Then I talk to the customer, get all the info and fix it very easily.

Good luck and let me know if I can help.

[Jace2010LGT]

Blown strut mounts on a brand new car? I vote for just loose.

 

Have a similar noise (I wouldn't call it thumping, seems to be more metallic based) and seems to coming from the rear passager side. I've taken the spare tire out and tighten everything back up (no help). I do have the 19mm rear sway bar installed, but I'm not ready to declare it that. To me it seems to be from the seat latches but even with the seats down I still have the sound. It seems to resonate when transitioning the vehicle into a turn. I agree its something that drives crazy.

 

I know this may sound dumb but trust me. Remove your rear license plate and trim ring and drive the car. I've repaired cars with a metallic rub/bump by putting isolating felt under the license plate.

[EJ25subie05]

i vote its something with your suspension, maybe end-link, strut or such. I had a thumping noise as well and was a strut, and before on my is300 it was an end link

[GTEASER]

DeaconBob, be a little more specific please. A thumping like a dull muffled thud, or metallic banging sound?

[DEACONBOB]

Thank you everyone for posting! The noise sounds like its in the trunk and that's why I originally took out everything in it. When I took it to the dealer they pullrd down the heat shield around the muffler. The sound seems to be on the rear passenger side. Sounds like something bouncing around. Only happens when the rear is going over a rough section of road. When the windows are down the sound seems confined to the trunk and sounds no different as when the windows are up. I think its time to go back to the dealer and take the Tech for a ride!

[bsevic]

I just had my 2013 in for a sunroof issue and had them look into the noise also coming from the rear passenger side that I described earlier. Service Writer told my wife (since she was the one the brought the car in) that there's a technical service bulletin and they needed to order parts to resolve the noise, and that we will have to leave the car for two to three days (they are providing a loner). Not sure if the extended time is related to the new rails and cable for the sunroof or the noise issue.

 

Here's what I could find online " High-Pitched Sound from Extension Housing Area Using Latest Generation Production Part technical bulletin number "12-147-13 " not sure if this is the one they were referencing. I don't have a subscription to get the detail.

 

I guess I will find out next week.

[bsevic]

Here's some additional information on found.

 

Service Bulletin # 12-147-13

 

Bulletin Description: The purpose of this bulletin is to provide a repair procedure to address a customer concern of a "pop" type sound coming from the right rear wheel apron area. The sound may occur over bumps when a twisting motion is introduced into the vehicle chassis at low speeds. After verifying the customer’s concern and performing the procedure, be sure to road test the car again to confirm the sound has been eliminated.

[bsevic]

I purchased a three day subscription to Subaru's Technical Bulletins. 12-147-13 is 14+ pages and two large to upload to the site with all the pictures.

 

It's pretty involved event. They remove the right rear wheel, inner mud guard, then removing the undercoating where three layers of sheet metal are secured together via welds. Then they take a 2 x 4 (yes a 2 x 4) and flatten the outer wheel apron. And then use a template to punch 27 1.8mm indentations in this area. They then use a 3/16 tapered punch to increase them to 3mm. They then undercoat and put everything back together.

 

Any of you technical experts have opinion on what this procedure is accomplishing? And why only the right side (passenger side of the vehicle)? My guess is that bent metal is stronger then the flat metal in this area, so these 27 indentations increase the strength of the metal in this area?

 

2013 Subaru goes in today so I will let you know if this resolves the issue.

[minuccims]

So its the sheet metal that's popping. Interesting repair procedure; kindly bludgeon it.

[GTEASER]

Not bludgeon, tickle.

[BigBopper]

So its the sheet metal that's popping. Interesting repair procedure; kindly bludgeon it.

 

I think first, I would try a patch of soundproofing inside the right rear fender area in the trunk. Mark, you've been working in the trunk recently ... I've noticed some panels in that area that seem to be prone to resonance.

[minuccims]

I think first, I would try a patch of soundproofing inside the right rear fender area in the trunk. Mark, you've been working in the trunk recently ... I've noticed some panels in that area that seem to be prone to resonance.

 

Too funny. I was going to essentially type all of this in, but per coffee on cell phone = failure.

 

I will say the left wheel well differs from the right. There is a larger panel on the left. Can't now, put can look at the pictures taken and see if any are post worthy. I did put murder mat on the wheel wells to absorb vibration. Wonder if the construction technique changed. Taking off the liner is quite simple. As BB said, it may be easier to address this from the inside.

[bsevic]

Service Bulletin 12-147-13 resolved the issue in my 2013 Subaru. Looking at the Service Bulletin, Legacy with VIN > then D*038088 and Outbacks > then D*292979 have had this introduced in production.

[TheBoltman]

My 2011 Legacy 2.5i Premium has a popping noise behind the right passenger seat near the rear wheel. I call it a pop because the TSB does. It sounds like sheet metal on sheet metal but not to loud and not too deep so I know it's nothing to dense or big. I only hear the noise when turning or driving over a rough section of road though not every time. I got the Legacy used and the noise didn't surface until I had about 10K of my own miles on it. I did some research and found that many who had this same noise referenced TSB 12-147-13. On 2/7/14 I took the vehicle to my local dealership and had them work on it according to the TSB. This has resolved about 90% of the pops but I'm still hearing that 10%. I'm wondering if the work wasn't performed well or if there is something else that would or could be causing the sound? I have gutted the interior and can't see anything else that might be the cause. After taking everything out I feel the sound come from the car just under the bottom of seat back. I have even taken the fuel pump cover off to see if I can hear the pop better however it's about the same.

 

Also, I have a PDF copy of the TSB. If anyone wants it PM me with your email and I can send it to you.

[ncfree]

Ok. So I have this same popping that you're getting. Do you have any suspension mods? So my cars in he shop right now they're looking at this and I'll let you know. The service guy said there is some recals on these body styles the older ones. In which a weld or sheet metal is breaking under stress and is only if complained by the customer. Though the service guy said it's probably just a loose wire somewhere that's banging on stuff but I doubt it. I'll let you know. Have any other info on this yet?

 

 

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