Right rear clunk when hitting bumps

ravenofpoe

Member
Jun 23, 2019
40
7
18
32
Clackamas or
I know there are multiple other threads talking about noise in the rear but none match my specific issue. So I decided to make a new thread.

I’ve got a 2017 gt performance package with just over 20k on the clock. When I go over bumps, speed bump, pot hole, plate in road, the car makes a clunk noise. Mostly sounds like it’s coming from the right rear corner but also sounds like it’s coming from the trunk. Doesn’t sound like it’s coming from the left at all and doesn’t happen when turning. It’s not there at very low speeds but is present at any speed that disrupts the rear end. At first I thought I had something bouncing in the trunk but there’s nothing loose back there. I recently had new mufflers put on because the previous owner did a muffler delete. Was too loud for me. It’s stock otherwise and was done by an exhaust specialist. The car drives straight, accelerates and stops hard like it should but that noise is starting to freak me out. Any ideas?
 
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ravenofpoe

Member
Jun 23, 2019
40
7
18
32
Clackamas or
They put it on a lift and we poked around. The only thing I learned was that the car has been lowered but appears to be on factory parts. I think it was 1 1/2 inch in front and 1 inch in rear or something. I forget now. They had trouble getting me on their lift.

That being said neither me nor the two techs that looked around can find anything. Even the counter girl came out and poked around a bit. At this point I've learned to ignore it.
 

Slow92Vert

Member
Aug 8, 2019
13
7
13
31
Walnut Park, CA
Hello @ravenofpoe
I had this EXACT issue on my 2015 Mustang Eco boost Coupe. It was not a rotating noise, but It also didn't sound like it came from a suspension component. I had no noise at Low speeds 1-10 MPH. To me it seemed like a loose nut inside of my rear fender. I did a couple of things.

1. Lifted The rear end, and removed both wheels
2. Visually Inspected the struts/Springs and wiggled every component that was accessible to detect movement. Nothing moved, or made noise.
3. I placed my rear seats down and rode inside the trunk while my girl friend drove inside of a large parking lot.
4. From there I realized that whatever was causing that sound was large enough to create a physical characteristics
5. I placed my hand on the tire well, and I can fell a faint movement that matched the sounds.

Anyways, I never found the cause for the sound. But I did find a fix. I lowered the car with eibach sport springs. After the springs where installed the sound was completely gone.