Need some help with 2012 GT shaking/shimmy 60mph+

[MisterFurious]

Chasing a shimmy in my Mustang that is breaking me. It is very noticeable starting at 60mph and around 70mph its very bad. It's a side to side shake, or shudder--my mirror is shaking left/right, dash, gauges, etc. It is still there when I push the clutch in at 70mph and the RPMs fall, so it is not RPM related, only MPH. I've had multiple alignments, at different shops, no change.
Car was stock with factory 19" wheels and started doing it about 85k. It's now at 108k, and still doing it. In the process of maintenance and upgrades I have had the following parts replaced, in the last year. NONE of which has solved this issue:

20" Shelby rims (I've tried two completely different sets of NEW tires, both sets road force balanced with little weight, no change is shake. They are staggered, so I cannot swap them) I originally thought one on the factory rims was bent, but no change in the shake with either set of rims.
Power Stop extreme full brake kit
GodSpeed MAXX coilovers
New Front control arms/ball joints
New adjustable end links
Just spent $2000 on aluminum driveshaft and new trans mount (vibration miss diagnosed by shop--STILL HAVE THE SAME SHAKE)
Front end alignment 1 month ago
Tires have 500 miles on them

There is no noise coming from the front hubs/bearings, and no play in the wheels when on the lift.
My head is going bald from scratching it at this point. Help me S197 forum PLEASE!

 

[JC SSP]

First, common misconception... alignment does not cause a shake, vibration, etc. but a pull, wandering, poor tire wear and handling.

Does it go away above 70MPH? Has the car ever been wrecked?

From what you have posted its something in the front end (i.e., dash shake). Not sure why invest $2k in all the driveline replacement & trans mount, but I get it you're trying to figure this out.

Consider checking: steering rack, shaft and column. Also, motor mounts, strut mounts, etc. Anywhere where the body is bolted to a subframe or suspension part where vibration is being transmitted through...

 

[MisterFurious]

The car hasn't been wrecked. It doesn't go away at 70mph. It gets worse. I spent the $2k, because a shop with a very good reputation told me the driveline vibration was transferring up the sub frame to the front end causing the shake. The 2 piece driveshaft needed to be replaced because the bearing was bad, they didn't notice anything loose or bad in the steering or motor mounts, I've replaced nearly everything else on the front end, this was the third shop I'd been to (the others found nothing), so I was really hoping they were on the right road. They weren't.

 

[OX1]

The car hasn't been wrecked. It doesn't go away at 70mph. It gets worse. I spent the $2k, because a shop with a very good reputation told me the driveline vibration was transferring up the sub frame to the front end causing the shake. The 2 piece driveshaft needed to be replaced because the bearing was bad, they didn't notice anything loose or bad in the steering or motor mounts, I've replaced nearly everything else on the front end, this was the third shop I'd been to (the others found nothing), so I was really hoping they were on the right road. They weren't.

Anyone do an actual vibration analysis?? I bought an app for my phone that was $100 and seems to work pretty well. I'm sure the pro equipment is 1000 times better than that. Use any remote cameras on wheels, suspension, steering, driveshaft, to see if anything is visibly shaking.

I would also not rule out new one piece driveshaft. Some have caused vibes upon installing a one piece. Most claim they are OK (with one piece), but if you just replaced one vibrating DS (due to wear) with another (due to geometry), how would you ever know?

 

[msvela448]

Do you have the "band clamp" type TPMS sensors? I had a similar situation and it turned out one of the bands was slightly loose and was able to move around the rim slightly, changing the wheel balance. I switched to the valve-stem style TPMS sensors and had my wheels rebalanced and everything went away.

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[Robert Larimer]

The car hasn't been wrecked. It doesn't go away at 70mph. It gets worse. I spent the $2k, because a shop with a very good reputation told me the driveline vibration was transferring up the sub frame to the front end causing the shake. The 2 piece driveshaft needed to be replaced because the bearing was bad, they didn't notice anything loose or bad in the steering or motor mounts, I've replaced nearly everything else on the front end, this was the third shop I'd been to (the others found nothing), so I was really hoping they were on the right road. They weren't.

Since you have replaced everything else the only thing left is a bent or damaged axle. Did anything happen at 85K that might have done that? The axles in our cars is pretty tough but can you check yours out? Does the car "pull" when you let go of the wheel at lower speeds?

2. Uneven Or Bent Axles, Driveshaft
Uneven or bent axles are another common cause of car vibration. The axles of your car are the long, rotating shafts that attach to your wheels, and drive power from your transmission into them.

Though they’re quite durable, axles can be bent by collisions, driving into a ditch, or driving over a speed bump or an object on the road. If this happens, you’ll feel your car start to “jostle” as you drive – and this vibration will usually increase in intensity as you drive faster.

https://www.ridetime.ca/blog/why-is...s are misaligned,the problem will be resolved.

 

[MisterFurious]

Anyone do an actual vibration analysis?? I bought an app for my phone that was $100 and seems to work pretty well. I'm sure the pro equipment is 1000 times better than that. Use any remote cameras on wheels, suspension, steering, driveshaft, to see if anything is visibly shaking.

I would also not rule out new one piece driveshaft. Some have caused vibes upon installing a one piece. Most claim they are OK (with one piece), but if you just replaced one vibrating DS (due to wear) with another (due to geometry), how would you ever know?

Pretty sure it was never the driveshaft because RPMs don't affect the shake, only MPH

 

[MisterFurious]

Do you have the "band clamp" type TPMS sensors? I had a similar situation and it turned out one of the bands was slightly loose and was able to move around the rim slightly, changing the wheel balance. I switched to the valve-stem style TPMS sensors and had my wheels rebalanced and everything went away.

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is there any way to tell without removing the tire?

 

[MisterFurious]

Since you have replaced everything else the only thing left is a bent or damaged axle. Did anything happen at 85K that might have done that? The axles in our cars is pretty tough but can you check yours out? Does the car "pull" when you let go of the wheel at lower speeds?

2. Uneven Or Bent Axles, Driveshaft
Uneven or bent axles are another common cause of car vibration. The axles of your car are the long, rotating shafts that attach to your wheels, and drive power from your transmission into them.

Though they’re quite durable, axles can be bent by collisions, driving into a ditch, or driving over a speed bump or an object on the road. If this happens, you’ll feel your car start to “jostle” as you drive – and this vibration will usually increase in intensity as you drive faster.

https://www.ridetime.ca/blog/why-is-my-car-vibrating-the-5-most-common-reasons/#:~:text=If your wheels are misaligned,the problem will be resolved.

I haven't had anyone pull the axles out to inspect, but "jostle" is a good descriptor--feels like I have a clothes dryer full of wet towels mounted to the front of my car.

 

[OX1]

Pretty sure it was never the driveshaft because RPMs don't affect the shake, only MPH

Driveshaft is connected directly to rear diff and is the only other driveline component (cept wheels/tires) that spins exclusively faster, in relation to MPH.

 

[OX1]

Since you have replaced everything else the only thing left is a bent or damaged axle. Did anything happen at 85K that might have done that? The axles in our cars is pretty tough but can you check yours out? Does the car "pull" when you let go of the wheel at lower speeds?

2. Uneven Or Bent Axles, Driveshaft
Uneven or bent axles are another common cause of car vibration. The axles of your car are the long, rotating shafts that attach to your wheels, and drive power from your transmission into them.

Though they’re quite durable, axles can be bent by collisions, driving into a ditch, or driving over a speed bump or an object on the road. If this happens, you’ll feel your car start to “jostle” as you drive – and this vibration will usually increase in intensity as you drive faster.

https://www.ridetime.ca/blog/why-is-my-car-vibrating-the-5-most-common-reasons/#:~:text=If your wheels are misaligned,the problem will be resolved.

Along those lines, what about a bent axle tube? Haven't some busted the crappy plug weld at the drag strip on the newer 8.8's? IF somehow, an axle tube bent slightly right around that mileage, might be contributing factor (although I think it would wear out tires quick, much more than create a killer vibration, if axle shafts them selves were not bent).......

 

[msvela448]

is there any way to tell without removing the tire?

When I bounced one of my tires (like a shop sometimes does when they take a tire off with a car in a lift) you could hear the band making a "twang" sound. None of the other ones made that sound.

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[JEWC_Motorsports]

Your 2012 doesn't have band tpms sensors. What does the diff upper bushing look like? Has the pinion angle been checked? Bushings on lca's, what do they look like? Lots of stuff to check to make an accurate diagnosis.

 

[MisterFurious]

Your 2012 doesn't have band tpms sensors. What does the diff upper bushing look like? Has the pinion angle been checked? Bushings on lca's, what do they look like? Lots of stuff to check to make an accurate diagnosis.

I'll get underneath it tomorrow AM and check those bushings

 

[MisterFurious]

Thank you for everyone's responses so far--you give me hope!

 

[Dino Dino Bambino]

You might also want to check if the lug nuts seat correctly in the rims. This can sometimes be a problem when aftermarket rims are used.

Pretty sure it was never the driveshaft because RPMs don't affect the shake, only MPH

A vibe from the driveshaft (worn center carrier bearing or worn universal joint) would precisely be MPH related. However since you've already replaced the driveshaft, it's unlikely the new one would vibrate unless there's either a factory defect or one of the balance weights has come off.

Along those lines, what about a bent axle tube?

A bent axle shaft from a previous accident would definitely 'cause a vibe. Depending on which direction it's bent, you may also see uneven tire wear.

 

[JC SSP]

I have always thought that a bent axle will produce a rear vibration, wobble or poor tracking (i.e., crab walk)... Not really a dash shaking, which is indicative of a front end issue... even a bad DS will produce vibration up through the transmission tunnel and into the cockpit, but he's only experiencing shake in the dash area?

Let's take the rear end issue out of the equitation... Put the rear up on jack stands and BLOCK/CHOCK the front tires so car does not roll away! Put the car in gear...Then watch from each side rear-to-forward along the body lines if the tire/rim assembly has any pronounced wobble. Being it's a manual gear box this might be a 2-person job, but you should be able to stick it in 1 or 2 and let it slow roll... You do NOT want to go up to 70MPH, only slow turning the rear tires to see if axle, wheel or housing is warped.

 

[2011/5.0]

And we removed the washers off the studs before we put the 20s on?

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[Gladams]

Would disconnecting the one piece shaft and rotate it half a turn, reconnect it and see if it gets worse or better help?

 

[MisterFurious]

You might also want to check if the lug nuts seat correctly in the rims. This can sometimes be a problem when aftermarket rims are used.



A vibe from the driveshaft (worn center carrier bearing or worn universal joint) would precisely be MPH related. However since you've already replaced the driveshaft, it's unlikely the new one would vibrate unless there's either a factory defect or one of the balance weights has come off.



A bent axle shaft from a previous accident would definitely 'cause a vibe. Depending on which direction it's bent, you may also see uneven tire wear.

I've checked with two sets of lug nuts, both seat well, and the shaking wasn't affected, so I don't think that's an issue.