Suspension Modifications and Noise - Advice Sought

[Madlock]

I've recently upgraded my '13 Coupe's suspension with Shelby Relocation Brackets, Billet LCAs, Adjustable UCA, FR-3 springs and bars and Shelby Adjustable Sway Bar Links. I also had installed a WhiteLine Watts Link.

 

I love the handling improvements. The stance is much lower with much-improved launch bite and sharper turn-in. The rear stays planted like never before, especially under acceleration over bumps when it otherwise would've tried to kick-out.

 

My only regret about installing the entire suite at once is not being able to attribute every specific improvement to a specific component or combination thereof. The same has proved true for trying to track down and correct the source of some undesirable consequences, namely the kind of metal-on-metal clanking and clunking I hoped to prevent by choosing components so carefully.

 

I'm hoping others who followed similar paths may have successfully resolved similar issues and may be able to recommend some solutions.

 

The most notable issue is a clunk upon initial acceleration that now occurs at almost any speed and in any gear. The likeliest culprit seems to be the Adjustable UCA, despite being torqued within a millimeter of its life. One drivetrain change made during the installation was allowing for -1.5 degrees of negative pinion angle to allow the driveshaft to "climb into" zero degrees relative to the differential under load.

 

Before reverting to reinstalling individual OE components to identify the cause by process of elimination, I'm wondering if anybody else has had a similar experience and success resolving it with the up-rated hardware in-place.

 

Can anybody offer a qualified opinion as to whether the negative pinion angle may be the culprit? If so, it's precisely the kind of thing the Adjustable UCA should allow me to dial-out. Otherwise, I'm considering the non-adjustable Shelby UCA, despite the fact that it shouldn't be any less susceptible to metal-on-metal NVH than the adjustable version. It'd be just one less potential source.

 

The WhiteLine Watt's Link performs brilliantly from a handling perspective, but I'm afraid even its bushing-based design doesn't completely eliminate metal-on-metal NVH which isn't quite as pronounced as spherical Heims and mostly occurs at lower speeds when the chassis and axle movement relative to one another occurs more slowly.

 

Even a good re-torquing after 200 miles hasn't eliminated the noise entirely - something of a disappointment given its promising design. I wish WhiteLine would offer more traditional urethane bushings as an alternative to their "Elastomer" product. Dynamat will clearly help dampen some of the stiffer components' additional transmitted resonance, but the most significant sounds are metal-on-metal contact, the kind that shouldn't exist to begin with and sound insulation won't remedy.

 

I'd appreciate any helpful guidance.

[svt13]

I thought we don't care about NVH mr.madlock .

 

Anyways I believe your clunking is coming from the UCA. Going to steeda will make it worse. I get a slight clunk too when I shift sometimes and if I floor it so the sudden weight change creates the clunk. My pinion angle is 0 so I don't think your pinion angle is the problem.

 

I don't think its the watts link. Since now I have the same one on and I'm pretty sure it's not responsible for my slight clunk but again my mechanic is going to check this all out tomorrow. I'm more worried about my whirrling sound that I am hearing. i am surprised you don't hear something similar like a noise that is now in the background of everything else.

[Mr. Haney]

The metal to metal clunk upon quick throttle changes could be the backlash of the gear set in the rear axle. When the driveline is free floating under a no load situation any change in throttle position will cause the contact between the ring and pinion to change. You may be hearing the gears making contact with each other as they float back and forth on the backlash adjustment in the rear. You won't get rid of this without replacing UCA and LCA with the stock pieces.

[0201212]

It's gonna be hard to have the ride quality and grip that you have while also reducing nvh. I would suggest soundeadner in the trunk and under the rear seat as this may atleast make I more tolerable. I have a lot of suspension mods on my car and the sound used to bug the cr@p out of me but I have gotten used to it now and it no longer bugs me.

[jnf]

Madlock, I had a similar issue when I did my 07. Heard the clunk upon accel.

The clunk turned out to be a bad spherical bearing in one of the LCA's.

I was completely frustrated with it and found it by grabbing the LCA while the car was on the ground and pulling on it.

This immediately reproduced the noise that I was hearing even though it was a sideway motion versus a forward under acceleration.

Not sure if you have spherical bearings where the LCA's meet the axle, but thought it was worth a shot.

Or any spherical bearings for that matter.

[Kevin Patten]

Madlock / svt13 - if both of you still have your stock driveshaft in your cars then both of you should go back to the stock UCA and make sure that you torque down the UCA bolts while the suspension is loaded.

[Madlock]

The metal to metal clunk upon quick throttle changes could be the backlash of the gear set in the rear axle. When the driveline is free floating under a no load situation any change in throttle position will cause the contact between the ring and pinion to change. You may be hearing the gears making contact with each other as they float back and forth on the backlash adjustment in the rear. You won't get rid of this without replacing UCA and LCA with the stock pieces.

 

 

How do the stock stamped components differ in this respect? If anything, the billet and tubular nature of the up-rated UCA and LCAs should yield less driveline "float", no? The ring and pinion position are going to change relative position upon transitioning from no-load to acceleration in either situation, no? If this is the case, it sounds like negating the negative pinion angle would be the best way to eliminate the ring and pinion as a potential, correct?

 

It's gonna be hard to have the ride quality and grip that you have while also reducing nvh. I would suggest soundeadner in the trunk and under the rear seat as this may atleast make I more tolerable. I have a lot of suspension mods on my car and the sound used to bug the cr@p out of me but I have gotten used to it now and it no longer bugs me.

 

 

Ride quality and overall NVH are fine. It's the acceleration clunk that's of primary concern and most troublesome. The nominal Watt's Link shift sounds aren't nearly as pronounced and I'll learn to live with them - I just want to ensure I know what they're attributable to.

 

Madlock, I had a similar issue when I did my 07. Heard the clunk upon accel.

The clunk turned out to be a bad spherical bearing in one of the LCA's.

I was completely frustrated with it and found it by grabbing the LCA while the car was on the ground and pulling on it.

This immediately reproduced the noise that I was hearing even though it was a sideway motion versus a forward under acceleration.

Not sure if you have spherical bearings where the LCA's meet the axle, but thought it was worth a shot.

Or any spherical bearings for that matter.

 

 

Thanks for the suggestion, but I don't have a spherical bearing in the whole of the suspension. The non-adjustable BMR UCA sounds like the way to go, as the adjustable version seems to be clunk-prone for some reason. Others have recommended welding the BMR UCA to alleviate its clunk, but I don't understand what that would achieve that properly ratcheted-down jam nuts won't. It sounds like that particular component's adjustability comes fraught with a particular downside that's probably an acceptable trade-off to those for whom such a wide range of pinion angle adjustments is necessary. I wish I knew before ponying-up nearly $300 for the adjustable UCA.

[svt13]

Madlock / svt13 - if both of you still have your stock driveshaft in your cars then both of you should go back to the stock UCA and make sure that you torque down the UCA bolts while the suspension is loaded.

 

 

My mechanic said if I go back to stock UCA then we can't adjust the pinion angle properly most likely. And why would we change out the carbon fiber driveshaft?

 

Idk about madlock but my entire car was torqued while the suspension was loaded but I do get that metal on metal clunk with sudden acceleration changes and jerks from shifting mostly downshifting. Though today I didn't get it as bad for a second I thought it went away.

 

That and the weird whirrling sound are the only new sounds I hear. Also I can't remember if I had it or not before but sometimes I feel the exhaust bubbling inside the car more now. But only sometimes.

[Kevin Patten]

First time that you have mentioned a CF driveshaft .

[jsarkis]

I changed my UCA to J&M's double adjustable street version (vs steeda's with the proper spacer) no clunk any more on acceleration. I also went with a more aggressive pinion angle -2, but my car isn't lowered.

[MMcGuirk]

First time that you have mentioned a CF driveshaft .

 

 

Original equipment on a 2013 GT500

[2010KonaBlueGT]

First time that you have mentioned a CF driveshaft .

 

 

They come on '13 GT500's.

 

Whatever you do, if you have a '07-'10...DO NOT BUY A PST CARBON FIBER 1-PC DRIVESHAFT. At least not until further review.

 

Mine failed with 585 miles on it. It twisted the aluminum yoke out of the inside of the carbon fiber tube. That was on OEM *Street* tires, on a public road (NOT a prepped launch pad at a drag strip with sticky tires) on a 2nd gear 'short-shift' (NOT a WOT speed shift!). Neither VMP or PST has done anything towards correcting the situation at this point in time so I have a $1200 paper weight sitting in the corner of my garage right now and a stock 2-pc driveshaft in my car.

 

Stephen at VMP has been working on it with PST....for OVER 3 MONTHS NOW but my position is, I BOUGHT IT FROM VMP, NOT FROM PST so VMP needs to step up and get this shit taken care of.

 

I'm getting real short on patience right now......

 

 

 

Phill

[Kevin Patten]

Original equipment on a 2013 GT500

 

Well then there should not be any angle problems with going back to the stock UCA .

[svt13]

Well then there should not be any angle problems with going back to the stock UCA .

 

 

Doesn't the angle change once the car is lowered though? Woudn't that be the reason for an adjustable UCA in the first place?

[Kevin Patten]

Just have your mechanic put the stock one back in and drive the damn car .

[07SGT2899]

i agree with the backlash theory

 

i've always found aftermarket UCA's to make a car very noisy and clunky inside. don't forget, you've taken out a stock, complient and insulating rubber bushing and replaced it with a stiff and hard, non-complient poly bushing in a mechanically noisy part of the car. right above the differential that has several moving parts inside all with their own clearances. you're bound to hear some clunking.

 

i would put the stock UCA back on and go from there

 

on a side note, on a 2k GT i had i put steeda poly bushed uppers on it and combined with the rear seat delete i could've swore the rear end was shot. i took it (the diff) all apart just to see there was nothing wrong with it at all and all clearancs were perfectly in spec, so in my personal experiance, poly bushed UCA's are the source of alot of noise and clunking

[07SGT2899]

Doesn't the angle change once the car is lowered though? Woudn't that be the reason for an adjustable UCA in the first place?

 

 

in my personal experiance, lowering even an inch and a half doesn't change the pinion/driveshaft relationship angle enough to matter or even be noticable on a street/occasional strip car

[Mr. Haney]

How do the stock stamped components differ in this respect? If anything, the billet and tubular nature of the up-rated UCA and LCAs should yield less driveline "float", no? The ring and pinion position are going to change relative position upon transitioning from no-load to acceleration in either situation, no? If this is the case, it sounds like negating the negative pinion angle would be the best way to eliminate the ring and pinion as a potential, correct?

 

It's the acceleration clunk that's of primary concern and most troublesome.

 

 

You mistook what I'm describing as driveline float as in axle movement. What I'm speaking of is, the ring and pinion gear inside the axle housing. Nobody can assemble a ring and pinion gear set with a constant mesh of the gears. What I mean by this, is the gear set......... is set up with an air gap between them. This air gap is measured and is called backlash between the ring and pinion. As you apply power to the pinion gear it rotates until it strikes the ring gear, then the ring gear transmits power to the differential, which in turn spins the axles. The backlash measurement allows for the driveline to float with no load if you equalize the engine RPM and load from the engine to the tires. The transmission also has backlash built into it. No gear set can be built where there is no free float of the gears. Otherwise they would destroy themselves as the expand and contract to hot or colder temperatures. If you jack the car up........disconnect the driveshaft..........grab the pinion yoke flange of the rear axle and rotate it back and forth by hand..........you will be able both see the flange has play in it and hear the pinion gear strike the ring gear. Float the driveline while driving the car by equalizing the RPM of the engine to the given road speed of the car..........apply power and you can hear the clunk of the pinion gear striking the ring that the factory rubber bushings eliminated. You may be also starting to get the same sounds traveling down the driveshaft to the rear from the transmission amplifying what you're hearing. These sounds are normal..........you are only now hearing them because you reduced the size and changed the material of the factory UCA and LCA bushings that hold the rear axle assembly to the car. If we were dealing with a full frame car and preformed these types of suspension modifications, the body to frame bushings wouldn't allow the noise to transfer into the interior cabin of the car. Since we are dealing with a unibody construction, driveline noises travel into the interior cabin very easily with modified suspensions. If this is the problem I doubt that changing brands of UCA or LCA will get rid of it.

 

swvt13........the whirling noise is the ring and pinion meshing together and again won't be eliminated.......it is a normal sound of the gear set. A whining sound from the rear axle, is a gear set that is set up wrong and can be plain heard as such.

 

I don't know where you are located in the DC region, but I'd bet my car isn't much louder than yours inside with my spherical bearings holding the rear in place. This is why I told you earlier that one persons interpretation of noise and yours was going to cause you problems. What I understand as normal noise transmission with the modifications performed and acceptable to my tolerance level for them and yours is two different things. This is why I advised you not to perform any mods. I am going to be busy for most of the weekend, but you can ride in my car to listen to what I've tried to tell you all along Sunday morning if you'd like......as long as it isn't raining

[svt13]

You mistook what I'm describing as driveline float as in axle movement. What I'm speaking of is, the ring and pinion gear inside the axle housing. Nobody can assemble a ring and pinion gear set with a constant mesh of the gears. What I mean by this, is the gear set......... is set up with an air gap between them. This air gap is measured and is called backlash between the ring and pinion. As you apply power to the pinion gear it rotates until it strikes the ring gear, then the ring gear transmits power to the differential, which in turn spins the axles. The backlash measurement allows for the driveline to float with no load if you equalize the engine RPM and load from the engine to the tires. The transmission also has backlash built into it. No gear set can be built where there is no free float of the gears. Otherwise they would destroy themselves as the expand and contract to hot or colder temperatures. If you jack the car up........disconnect the driveshaft..........grab the pinion yoke flange of the rear axle and rotate it back and forth by hand..........you will be able both see the flange has play in it and hear the pinion gear strike the ring gear. Float the driveline while driving the car by equalizing the RPM of the engine to the given road speed of the car..........apply power and you can hear the clunk of the pinion gear striking the ring that the factory rubber bushings eliminated. You may be also starting to get the same sounds traveling down the driveshaft to the rear from the transmission amplifying what you're hearing. These sounds are normal..........you are only now hearing them because you reduced the size and changed the material of the factory UCA and LCA bushings that hold the rear axle assembly to the car. If we were dealing with a full frame car and preformed these types of suspension modifications, the body to frame bushings wouldn't allow the noise to transfer into the interior cabin of the car. Since we are dealing with a unibody construction, driveline noises travel into the interior cabin very easily with modified suspensions. If this is the problem I doubt that changing brands of UCA or LCA will get rid of it.

 

swvt13........the whirling noise is the ring and pinion meshing together and again won't be eliminated.......it is a normal sound of the gear set. A whining sound from the rear axle, is a gear set that is set up wrong and can be plain heard as such.

 

I don't know where you are located in the DC region, but I'd bet my car isn't much louder than yours inside with my spherical bearings holding the rear in place. This is why I told you earlier that one persons interpretation of noise and yours was going to cause you problems. What I understand as normal noise transmission with the modifications performed and acceptable to my tolerance level for them and yours is two different things. This is why I advised you not to perform any mods. I am going to be busy for most of the weekend, but you can ride in my car to listen to what I've tried to tell you all along Sunday morning if you'd like......as long as it isn't raining

 

 

So you hear the same whirrling background sound that is prevelant when the car moves generally? If this is true and my mechanic agrees with your assessment then I will return the whiteline UCA and just get the roush UCA. It seems though the watts link and LCA were fine to use its just that stupid UCA. I guess no matter what there is no UCA on the market that is quiet like stock because that stupid thing is mounted right on the body. And apparently dynamat would help this situation.

 

How far are you from bethesda?

[Kevin Patten]

Don't put in the Roush one just put the stock one back in and save some time & $$. You can always buy more dynamat .

[svt13]

Don't put in the Roush one just put the stock one back in and save some time & $$. You can always buy more dynamat .

 

 

Well the roush one apparently cures the wheel hop as well but stays stock. I just wanted to see if I could get away with the magical white line one

[Kevin Patten]

If you are referring to Roush #421120 - you should call and let them know that you have lowered the car and ask if it is applicable ( Hey it's only another $300 spent ) and do you need it? Are you having rear wheel hop if you just put the stock one back in and leave your other mods "as is" ?

[svt13]

If you are referring to Roush #421120 - you should call and let them know that you have lowered the car and ask if it is applicable ( Hey it's only another $300 spent ) and do you need it? Are you having rear wheel hop if you just put the stock one back in and leave your other mods "as is" ?

 

 

Never really had wheel hop to begin with. The point for the UCA/LCA install was for weight savings and traction. Besides I get money back for returning the UCA if I do end up doing that.

[dave 316]

there are things when modding that you should be able to live with. not every change made is going to net the positive result you want, without a result you don't want. the factory sometimes uses things like rubber bushings that deflect, and control noise. the result is aftermarket companies being able to improve on the design, but often times with a tradeoff. this case NVH. When my car gets here, I want throttle body/pulley/cai/exhaust/gears. in reality i'm sure it will take me a while to go through with it because all of those things require a tune. Coming from a 1000 rwhp drag radial foxbody notch street car, and my '67 GTA vert, i'm familiar with modding and being able to do it all without the same PCM issues. i'm not concerned as much as you with warranty, its that i read horror stories about issues with tuners, and programmers, that i just not sure about wanting to tempt the negatives that come due to poor tuning. the best tuners in the world imo dont have the money to research and develop tunes that can make a car run the same in sub zero weather as it does at 110* and humid. ford tunes the pcm to do just that. with millions of dollars in research, and trial and blowing motors while doing it is the cost of doing business to give us the great product we have. with suspension bolt ons you can always go back to stock and people are non the wiser. PCM'S not so much! IMHO

[Madlock]

You mistook what I'm describing as driveline float as in axle movement.

 

 

You're absolutely correct. I did mistake it. Makes perfect sense now. Thanks.

 

I'm convinced the pinion angle isn't the issue, nor is the pinion/ring mating. I'm convinced I'm experiencing the same adjustable UCA clunk that's within the UCA itself, despite having also used the up-rated mount Shelby recommends to remedy what shouldn't exist to begin with. The decision from here is whether to use the non-adjustable version of the same product or restore the OE part that's subject to greater deflection. As much firmer as the stiffer components will make the ride, there's simply no reason for the adjustable UCA to introduce metal-on-metal impact noise absent design or production flaws that should keep it out of the catalog to begin with. It pisses me off to perhaps chuck $300 worth of hardware, let alone potentially invest another $150, especially if the clunk is owed to something beyond the arm's adjustment mechanism. Welding would be another way to go, but it remains too much of a one-way street for my preference.

 

Despite being lowered, the Ford Racing "L" springs don't introduce enough of a difference to create bump steer or a pinion angle beyond nominal tolerances with stock components. I'm fine going back to the stock pinion angle configuration (albeit with any variance the "L" springs introduce). I just hoped to take maximum advantage of the opportunity to make the pinion angle as aggressive as possible. I expected the firmer components and bushings to inherently transmit more resonance and the outcome is absolutely within my expectations. But I won't abide the metal-on-metal impact that shouldn't exist, especially in such a critical component as the third link.

 

Regardless of how I choose to resolve it, I'm looking forward to removing the part and seeing if any evidence of exactly where the contact is occurring becomes evident. Especially after having re-powder coated everything any signs of undue contact wear should be readily apparent. If not, it must be inside the adjustment threading. I hate to put up the car on a lift twice when once will do, but I'm likely to hoist it with the intention of reinstalling the OE UCA assembly and, based upon what I observe from the uninstalled adjustable UCA, make a decision whether to leave the OE UCA installed or re-complete the suspension upgrade with a fixed component.

 

I also happen to have on-hand Shelby's all-in-one adjustable assembly that includes its own rubber bump stop which seems to be a beautifully made, if not somewhat over-engineered piece. I might have been willing to install that piece instead once upon a time, but being so deep into this particular suspension component already has made me MUCH more conservative than I otherwise might've been in terms of how much more resources I'm willing to commit to this specific issue before waving the special teams onto the field. Otherwise, accessing the UCA bolt makes a perfect time to install Dynamat to compensate for the combined Rear Seat Delete's lesser insulation and up-rated parts' greater resonance conductivity potential.

 

Beyond that, I'm too happy with how settled the rear has become with the Watt's Link to back-out or head down a different path - even if an even-quieter alternative existed. I'd certainly be willing to try replacing WhiteLine's elastomer bushings with urethane or custom made Delrin substitutes to eliminate any incidental rattles even at the expense of further resonance which Dynamat should be able to tame.

[Kevin Patten]

Never really had wheel hop to begin with. The point for the UCA/LCA install was for weight savings and traction. Besides I get money back for returning the UCA if I do end up doing that.

 

That is IF they credit you back a refund !

[patrickshelby]

It all comes to bolt one part after the other and test drive the car in between.

It's not practical at all, but reading so many similar stories about clunks and NVH, it seems to be the only way to isolate culprit components...

The clunks and NVH related problems seems to come from aftermarket UCA's for most, though.

I had the Steeda adj. UCA on my car (Poly on the rear axle and spherical bearing on the frame bracket). I took it away after an hour drive.

I am not saying it's bad !!! I just say the advantage it brought was annihilated by the noise it generated FOR MY LIKING.

This winter, I will try the WHITELINE watts mounted on an otherwise all stock rear suspension at first...

[Kevin Patten]

You're absolutely correct. I did mistake it. Makes perfect sense now. Thanks.

 

I'm convinced the pinion angle isn't the issue, nor is the pinion/ring mating. I'm convinced I'm experiencing the same adjustable UCA clunk that's within the UCA itself, despite having also used the up-rated mount Shelby recommends to remedy what shouldn't exist to begin with. The decision from here is whether to use the non-adjustable version of the same product or restore the OE part that's subject to greater deflection. As much firmer as the stiffer components will make the ride, there's simply no reason for the adjustable UCA to introduce metal-on-metal impact noise absent design or production flaws that should keep it out of the catalog to begin with. It pisses me off to perhaps chuck $300 worth of hardware, let alone potentially invest another $150, especially if the clunk is owed to something beyond the arm's adjustment mechanism. Welding would be another way to go, but it remains too much of a one-way street for my preference.

 

Despite being lowered, the Ford Racing "L" springs don't introduce enough of a difference to create bump steer or a pinion angle beyond nominal tolerances with stock components. I'm fine going back to the stock pinion angle configuration (albeit with any variance the "L" springs introduce). I just hoped to take maximum advantage of the opportunity to make the pinion angle as aggressive as possible. I expected the firmer components and bushings to inherently transmit more resonance and the outcome is absolutely within my expectations. But I won't abide the metal-on-metal impact that shouldn't exist, especially in such a critical component as the third link.

 

Regardless of how I choose to resolve it, I'm looking forward to removing the part and seeing if any evidence of exactly where the contact is occurring becomes evident. Especially after having re-powder coated everything any signs of undue contact wear should be readily apparent. If not, it must be inside the adjustment threading. I hate to put up the car on a lift twice when once will do, but I'm likely to hoist it with the intention of reinstalling the OE UCA assembly and, based upon what I observe from the uninstalled adjustable UCA, make a decision whether to leave the OE UCA installed or re-complete the suspension upgrade with a fixed component.

 

I also happen to have on-hand Shelby's all-in-one adjustable assembly that includes its own rubber bump stop which seems to be a beautifully made, if not somewhat over-engineered piece. I might have been willing to install that piece instead once upon a time, but being so deep into this particular suspension component already has made me MUCH more conservative than I otherwise might've been in terms of how much more resources I'm willing to commit to this specific issue before waving the special teams onto the field. Otherwise, accessing the UCA bolt makes a perfect time to install Dynamat to compensate for the combined Rear Seat Delete's lesser insulation and up-rated parts' greater resonance conductivity potential.

 

 

 

You don't have an understanding of what "bump steer " is or you would not make that comment in regards to a solid axle, a solid polyurethane bushing UCA and LCA's go into bind as the solid rear axle wants to articulate - where do you think that you have a "metal to metal" contact on the UCA ? At the threads/jam nuts ? There should NOT be any gap there if you properly torqued the jam nuts. IMO the Shelby UCA is going to give you the same as you have now - you are better off going back to the stock UCA . As far as bite goes - use the height adjustments that you have on the LCA's . As far as pinion angle changes go on a 3 link solid axle during suspension travel it involves a relationship between the length of the upper arm in regards to the length of the lower arms and where they are at in the arch of their individual swing radius that determine how much and in which direction the pinion angle change occurs when the load/torque is applied. If you are reluctant to change out your UCA , then double check the clearance between the bolt and the sleeve on the 2 bolts of the UCA.

[TrakRat]

You may be hearing the differential gear lash thru the control arms. You may be hyper sensitive about any new noises as you've been obsessing over NVH throughout the build. There's a reason Ford had spongy rubber bushings everywhere.

[Madlock]

You may be hearing the differential gear lash thru the control arms. You may be hyper sensitive about any new noises as you've been obsessing over NVH throughout the build. There's a reason Ford had spongy rubber bushings everywhere.

 

 

No, it's not that. I've obsessed over nothing but but choosing the best components for my preferences and their proper installation. It's a repeatable clunk that shouldn't occur but has become a documented characteristic of a particular part after I happened to buy it. I'm far less concerned about noise than a future catastrophic failure after repeated, stressed impacts between whatever individual elements of happen to be involved that aren't designed or intended for withstand them. In this case, the noise is merely a useful symptom for identifying the problem.