Thump coming from rear-end - SSM

[JuanHuevos]

I recently developed a thump in the rear of the car somewhere (11,8XX miles). It's only upon acceleration and deceleration. It's an A10 so mostly when it downshifts while coasting. Under heavy acceleration, at high speed, smooth as glass. I was worried it was my Steeda Stop the Hop stuff so I removed the braces and the front diff bushing supports. That didn't help. I also took my Wengerd tune out just to get things back to stock as I thought maybe it was the trans. I took it to a the dealer this morning and had the tech ride with me so he could hear it. I trust these guys, I've done a lot of IT work for them so we have a good relationship. They just called and said there's an SSM against the car. That if you hear a thud/thump/clunk upon acceleration or deceleration, the half-shafts and hubs need to be replaced. So they've ordered those parts and the warranty will cover it. Hopefully that fixes it! Anyone else have a similar issue? I'm not sure if it's Mach 1 specific or not (the SSM).

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[526 HRSE]

You're not a coyote are you?

 

[JuanHuevos]

Looks like I'm not alone with this issue. SSM 52444. There's several posts about this.

 

[JuanHuevos]

Just to give an update, the dealer put in new axles and hubs per the SSM. No change. Clunk is still there. At this point I’ve removed all the Steeda Stop the Hop components except the subframe bushing reinforcement pieces and the subframe alignment dowels. I brought the car home due to a storm rolling through this weekend. It’ll go back next week for the adventure to continue.

 

[Aonarch]

Just to give an update, the dealer put in new axles and hubs per the SSM. No change. Clunk is still there. At this point I’ve removed all the Steeda Stop the Hop components except the subframe bushing reinforcement pieces and the subframe alignment dowels. I brought the car home due to a storm rolling through this weekend. It’ll go back next week for the adventure to continue.

I'm curious if that fixes it.

Under super rare conditions I feel a bit of a clunk too, but ignore it. It only happens under odd load transfer, uneven payment and with an incline or decline. Like pulling into a steep driveway with a break in the payment for drainage.

I have the full Steeda Ultimate Handling kit.

 

[JuanHuevos]

Well, the dealer called and said they fixed it. I went and picked it up and drove it home. The dealer removed the last of the Steeda parts, the subframe bushing supports and the subframe alignment pin/dowl/thingys. I just drove it home which is only a mile or 2 but did not hear the noise. I thought at one point I heard it but it was quieter or muted, but it could be in my head. So I will drive it to work tomorrow and see how it goes. My initial thought though, perhaps the subframe bushing supports are able to transmit that sound into the body and it is easier to hear. Maybe it's been there all along I just couldn't hear it before the Steeda parts. Now that they are back off, I can't hear it again. I don't know...it's frustrating.

 

[Aonarch]

Well, the dealer called and said they fixed it. I went and picked it up and drove it home. The dealer removed the last of the Steeda parts, the subframe bushing supports and the subframe alignment pin/dowl/thingys. I just drove it home which is only a mile or 2 but did not hear the noise. I thought at one point I heard it but it was quieter or muted, but it could be in my head. So I will drive it to work tomorrow and see how it goes. My initial thought though, perhaps the subframe bushing supports are able to transmit that sound into the body and it is easier to hear. Maybe it's been there all along I just couldn't hear it before the Steeda parts. Now that they are back off, I can't hear it again. I don't know...it's frustrating.

Factory bushing are super squishy and absorb what you were feeling before.

 

[JuanHuevos]

Factory bushing are super squishy and absorb what you were feeling before.

That was my thought, so the issue probably persists.

 

[S550HPP]

Yeah all these upgrades are usually a comfort and NVH downgrade.

Only sway bars, vertical links, end links and Ford Performance Control arms seem to be 100% non invasive.

My new Koni SA rear shock is making noise....good thing seller has great support.

 

[murick]

Joining the club . I just had Ultimate Steeda Kit installed with diff. bushings today and the guy who installed it told me right away that I have too much play in the differential (I have however an LSD, not Torsen) and that it manifests as the "clunk" when there is a change of power transfer (engine pulls vs car pulls) and showed it to me.

I can now reproduce it simply by shifting N->1, or 1->2 (I have Tremec) and during the shift it clunks. It does that also when driving down the slope and backing off the throttle.

Another new experience is a whine (I believe also from the diff. and possibly for the same reason), which I hear when coasting with just a tad bit of throttle basically in any gear or at any speed. If I go more on the throttle, or back off completely it goes away.

So it seems there are operational parameters where the diff (or something else of similar nature) becomes unstable. If the change is fast it clunks, and when the change is frequent it whines. Whether it is an example of the aforementioned SSM I have yet to find.

 

[JuanHuevos]

Joining the club . I just had Ultimate Steeda Kit installed with diff. bushings today and the guy who installed it told me right away that I have too much play in the differential (I have however an LSD, not Torsen) and that it manifests as the "clunk" when there is a change of power transfer (engine pulls vs car pulls) and showed it to me.

I can now reproduce it simply by shifting N->1, or 1->2 (I have Tremec) and during the shift it clunks. It does that also when driving down the slope and backing off the throttle.

Another new experience is a whine (I believe also from the diff. and possibly for the same reason), which I hear when coasting with just a tad bit of throttle basically in any gear or at any speed. If I go more on the throttle, or back off completely it goes away.

So it seems there are operational parameters where the diff (or something else of similar nature) becomes unstable. If the change is fast it clunks, and when the change is frequent it whines. Whether it is an example of the aforementioned SSM I have yet to find.

Your clunk sounds like mine. Mine does it when it shifts in either direction (A10) at certain speeds. Today, I talked to the mechanic from the dealer that worked on it. He mentioned that all the diffs in Mustangs whine but when you stiffen the rubber bushings, you hear it more. He said he's seen the whine be so bad they had to remove the bushing stiffeners. Once they were out, the whine could barely be heard.
He also said my clunk could still be there but if it's an actual malfunction, it will get worse over time. I'm not a fan of waiting on something to expire and leave me stranded so I'm going to keep pursing this.
The last bit of info he shared was about the alignment dowels for the subframe. He said from the factory there are holes in the body and subframe they use to align everything. He said he used those same holes and that is why he took the dowels out of my car.
You could always try that SSM, get new axles and hubs and see if it helps I suppose.

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