CaliGT500524

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Hi all,

I've got a 2010 GT500 with about 60K miles on the car. I've been noticing a vibration that is both felt and extremely audible from outside of the vehicle. The noise is most prevalent in 3rd and 4th gear and usually at about 1800-2000 rpm under heavy load. I have only really noticed the issue after having installed a McLeod RST Clutch.

-There a slightly less than smooth idle and I can create a minor vibration and shake in the engine/chassis when in neutral, not moving, and the clutch in or out. The idle however, is sometimes spot on, like you can't even feel the car running kind of smooth.
-When driving however, at points in the rev range where the vibration/lack of smoothness is at its worse, I will clutch in and hold the clutch in and rev the engine or hold the engine at that problem RPM and its gone.

Now, I suspected that perhaps something went awry with the clutch, so I pulled it out, took to the McLeod factory myself and had them check the stock flywheel and clutch balance, then mount the two together and mark the most perfect balance spot; which actually surprised the technician how in balance it was. I reinstalled the clutch and maybe it was a little better but overall still there.

I have also ruled out a driveshaft issue since I swapped the 2 piece stock unit for a Ford Performance one piece aluminum driveshaft. The vibration remained and maybe got a little worse.

My axle is making some weird noises and clunking under many driving scenarios and conditions, I redid all of the rear and front suspension, I mean its all 100% brand new. I suspect perhaps some wheel bearings at best and clutch packs at worst (different sounds). But this wouldn't explain the vibration/lack of smoothness in running during idle or the fact that it goes away when I clutch in while driving. I think this a whole other issue and I will most likely rebuild the differential.

Mods I have installed on the car:
-Engine: 2.6 Upper Pulley, JLT Big Air CAI, BBK 65MM Throttle Body, VMP Inlet Elbow
-Chassis/Suspension/Drivetrain: Lowering springs, adjustable lower control arms (Rear), adjustable panhard bar, Ford Performance One piece shaft, McLeod RST Clutch.

The noise and vibration are driving me up a wall and I cant seem to find good answers on other threads or forums. Engine mounts and the transmission mount look fine and I've had other technicians including Galpin look at this to verify my findings...nada. I don't suspect the harmonic balancer (noise isnt present when clutching in while moving at problem RPMs) per say and I don't necessarily suspect the transmission assembly itself either but its all possible.

Is it possible that something in the exhaust is creating this vibration since it seems to be RPM related? Maybe I'll look over the engine mounts again? You can really feel this minor shake (INCONSISTENT) through the seat, steering wheel, etc. Looking for some clues, maybe someone here has had this issue as well? Any input appreciated.

Thanks!
 

RedVenom48

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First thing id check is the balancer. With the car parked engine running, take a peak at the balancer and see if its wobbling. If it looks ok, this may be somethin you want a technician to look at. Considering a Ford tech looked at it, a speed shop, perhaps Mustang specific can look at it.
 

Catmonkey

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I'd remove the inspection plate and check the flywheel for runout. Who changed out the clutch? Did you change the pilot shaft bushing either time?
 

Black Cobra '99

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I'd check the driveshaft angle, it will vibrate if the angle is off and especially under load. Lowering springs will change the angle and the 1 piece driveshaft will make the vibrations worst.
 

CaliGT500524

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I'd remove the inspection plate and check the flywheel for runout. Who changed out the clutch? Did you change the pilot shaft bushing either time?

Yes, so that’s what I was getting at in my post. I too the flywheel and clutch to McLeod Racing’s facility. They checked the flywheel and clutch individually for runout and balance and both were good. Then they mounted both as one unit and checked the balance. We found the spot where balance was perfect.
 

CaliGT500524

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I'd check the driveshaft angle, it will vibrate if the angle is off and especially under load. Lowering springs will change the angle and the 1 piece driveshaft will make the vibrations worst.


I checked pinion angle and found it to be -1.75 degrees. Seemed like -2 was ideal with the range being -1 to -3 degrees. I can check again to be sure I guess.
 

Catmonkey

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What about the pilot shaft bushing? If it's bad or missing, it can cause the pilot shaft to not be centered and would tend to throw the clutch disk off center causing a balance issue.
 

CaliGT500524

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What about the pilot shaft bushing? If it's bad or missing, it can cause the pilot shaft to not be centered and would tend to throw the clutch disk off center causing a balance issue.

So the clutch was replaced just 2500 miles ago and the pilot bearing, clutch, throw out bearing, clutch line, were all replaced. They all still seemed really nice when I had the entire assembly out of the car a few days ago.
 

fullboogie

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May be two separate issues. Don't overlook something simple like a thrown wheel weight.
 

CaliGT500524

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May be two separate issues. Don't overlook something simple like a thrown wheel weight.

So in regards to specifically a wheel weight, I had all of the wheels rebalanced recently. Also, the vibration is rpm related and when I clutch in, the noise goes away at speed. If I bring the RPMs up to the point where the vibration was at its worst, while still moving, and being clutched in the engine is dead smooth. As soon as I start releasing the clutch pedal, the noise comes back.

I kind of checked things like the exhaust, loose brackets, mounts, etc. of course I could’ve missed something easy.

I’m wondering at this point if it’s something in the transmission like a bad input shaft bearing or maybe a synchronizer problem. I am having some shifting that isn’t 100% spot on all of the time.
 

mdoan

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What about sitting still, in neutral? If you run it up the rev range does it vibrate at any RPM?

I am 95% convinced you have a bad harmonic balancer. I also have a 2010, 62,000 miles, and I just changed mine. Between 1500-2500 rpm at any gear (including neutral) I'd get a nasty vibration that shook through the whole vehicle; it even rattled an interior panel somewhere. There was an ever so slight oscillation when looking at the balancer spinning, but not enough to raise concern at all. After inspecting the old unit once pulled, it looked EXACTLY like the new one. No rubber deformation; nothing visually wrong with it at all.

The rubber just deteriorates over time - being directly under the open hood vents doesn't help. As it deteriorates, the harmonic values it can absorb changes.

If you're getting vibration through the entire car, by far the most likely culprit is that balancer. It's a pretty simple job. You have to remove the fan, but once that's out, there's actually a lot of room to work. I was able to get an impact in there to remove the crank bolt easily. Hopefully you have - or can rent - an impact, as that bolt is torque to yield and if you break it with a breaker bar, you're looking at a complete engine tear-down. If you have any questions about the job, I literally just finished it, so feel free to PM me - I'll be happy to help. FYI there's not a pulley installer on the market that'll work with our crank, or that I could find. You'll need a 12mm x 1.5 thread rod or bolt that's something in the range of 140-200mm long. Removal is done with a 3-jaw gear puller. Again, please PM me and I can help with little details like those.

DO NOT DRIVE IT UNTIL YOU REPLACE THE BALANCER IF YOU CAN. I guarantee that's the culprit.
 
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