Vibrations Between 40-50mph

[SlowyoteJay]

I'm stumped guys.

I have a 2019 mustang gt 6pd, and whenever I'm driving from 40mph to 50mph (any gear from 2nd - 5th), the car starts to vibrate like crazy. I've changed out the transmission fluid, changed the diff fluid, had the driveshaft rebalanced and u joints swapped out, and wheels/tires rebalanced. The transmission shifts smoothly in every gear, but when I brought it to Ford for a diagnostic, they said it COULD be the transmission due to the previous owner not having the required transmission fluid amount, and possibly messing up some of the internals.

Has anybody heard of this happening? If it is the transmission, would it be better to just buy a new one or should I rebuild it?

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[KilgoreLSU]

This might sound stupid, but I've had this happen with TIRES... if you have a friend with the same car, swap wheels and see if it goes away.

 

[SlowyoteJay]

This might sound stupid, but I've had this happen with TIRES... if you have a friend with the same car, swap wheels and see if it goes away.

You think it might be the tires even if I only have roughly 5k miles on them?

 

[KilgoreLSU]

You think it might be the tires even if I only have roughly 5k miles on them?

Yes.. did it do it with the tires that were on there before?

I mainly have had this problem with off brand and Goodyear.. I always attributed it to bad luck..
I'm not saying this is the answer, but the easiest way to check for it is to swap tires and wheels with a friend.

 

[SlowyoteJay]

Yes.. did it do it with the tires that were on there before?

I mainly have had this problem with off brand and Goodyear.. I always attributed it to bad luck..
I'm not saying this is the answer, but the easiest way to check for it is to swap tires and wheels with a friend.

No it didn't do it before. I'm running Falken Pros at the moment. But I can always rotate them and see if the vibration is felt elsewhere. I actually never thought of that but it's something to try

 

[G.T.]

Agree on checking wheels/tires. Bad wheels/tires can show as balanced on a machine even if they shimmy (but they can be seen by the tech if he is on the ball).

A tire rotation should make things clearer too, if the vibrating characteristics change. If you start feeling it at the steering wheel high chance it was the rear wheel/tires causing the vibration.

Worn suspension bushings can cause them too.

 

[Geodudes550]

Always a good idea to check your alignment if you’re getting a shimmy.

 

[Blufc3s]

Mine was doing the same at the same speed as yours. Ford (under warranty) changed the driveshaft, roadforce balanced the wheels and didn’t cure it.
I read, on this site I believe, to put a hose clamp on the drive shaft and move it around with the weighted part in different locations until the vibraction was gone.
i did it a few years ago and its been fine ever since. I was ready to sell the car.

 

[SlowyoteJay]

Mine was doing the same at the same speed as yours. Ford (under warranty) changed the driveshaft, roadforce balanced the wheels and didn’t cure it.
I read, on this site I believe, to put a hose clamp on the drive shaft and move it around with the weighted part in different locations until the vibraction was gone.
i did it a few years ago and its been fine ever since. I was ready to sell the car.

So basically try rotating the driveshaft?

 

[Blufc3s]

So basically try rotating the driveshaft?

i tried that, didn’t help

 

[jonny10buds]

I had a vibration on my new 2019 Bullitt, the dealer didn’t want to know saying it’s a ‘sports car’ and is designed to vibrate, I downloaded this app which narrowed it down to the propshaft which they eventually replaced under warranty.

 

[SlowyoteJay]

I had a vibration on my new 2019 Bullitt, the dealer didn’t want to know saying it’s a ‘sports car’ and is designed to vibrate, I downloaded this app which narrowed it down to the propshaft which they eventually replaced under warranty.

Could it still be the driveshaft if the u joints have been replaced and it's been rebalanced?

 

[jonny10buds]

Could it still be the driveshaft if the u joints have been replaced and it's been rebalanced?

Probably not, the app will determine whether it’s wheel/tyre or propshaft related by the frequency of the vibration.

 

[Late Starter]

If you swap tires and feel the vibration in the seat, rather than the steering wheel, I suspect driveshaft imbalance. My 2017 vibrated at day one. Did the hose clamp trial and error method and got rid of 90% of it.

 

[SlowyoteJay]

Update: Rotated the tires but still no difference. Haven't driven the car in roughly 2 months, but now that I got to test it out, I'm pretty sure it is the transmission. The vibration is coming from the middle of the car where the transmission is. I have been looking to go with a calimer transmission so I guess this is my chance . Like I previously stated, driveshaft was rebalanced and u joints swapped out, tires rotated and balanced, alignment done as well, and trans fluid changed so the last thing left would be the transmission.

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