Custom Driveshafts - A fix to driveline vibrations or a cause for their increase?

[jmagnus87]

Ok so in the process this weekend, i would check the wheel bearings while you're at it. That's very faint of a shimmy but more than what i have for vibration through the wheel. There was a thing about bad wheel bearings falling pre-maturely but i thought it was exclusive to us gen 2 guys... how many miles are on it again?

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[noGreta!]

Ok so in the process this weekend, i would check the wheel bearings while you're at it. That's very faint of a shimmy but more than what i have for vibration through the wheel. There was a thing about bad wheel bearings falling pre-maturely but i thought it was exclusive to us gen 2 guys... how many miles are on it again?

900!

 

[silverbullet85]

I bought a stock one from the dealership and installed it myself so I could make sure everything was re-assembled correctly and torqued properly. I would honestly check the mark on the flange to the rear most weight on the driveshaft. Mine came from the factory with the weight aligned to the mark, which is the "high side" of the rear. Typically you would not want those two together. I would be willing to bet I could have rotated the flange, bolted back together and it would have been good to go.

What your saying makes sense in your case but a driveshaft doesn't go out of balance on its own in a 1000 miles of driving or any driving unless it has been damaged or incorrectly installed, if the movement is in his wheel it has nothing to do with the driveshaft. Op you could jack up the rear of the car and go through the gears and if the vibration is still there then it's in the rear if it doesn't come back the problem is in the front. Is it possible you braked aggressively enough that you warped the brake rotors?

 

[jmagnus87]

900!

Yeah there's no way in hell you did anything wrong yourself. Forget the wheel bearing thing. I'm with the other guy that said driveshaft was installed incorrectly. Seems to be the most logical to me!
i
I guess i was grasping at straws trying to think of anything that might do it with driveshaft rpm, dude was right, i was thinking of when you change differential gears

 

[noGreta!]

Yeap. It was the same with the 2021. Two or three days after leaving the dealership - the car wasn't even broken in and ... shimmy town... Ford dealer response: "within spec - it's a sports car dude it ain't gonna be smooth"...

 

[RagmopInKona]

lol ... it wouldn't be the first time but I had friends drive both cars and they agree with me. The Ford service department agrees with you though that the problem is me

For what is worth, the shimmy/vibration is worse in very smooth roads.

I will try to take a video soon.

Thank you all for the replies.

You sure it isn't the car tramlining at speed and you feeling it in the steering wheel?
A driveshaft issue is not going to show up in the steering wheel.
You got the lane keep system off. that shakes the wheel if it thinks you are drifting out of your marked lane?

 

[jmagnus87]

If the driveshaft is shaking the differential, the differential is connected to those super squishy bushings which could mean the two rear tires are shifting ever so slightly back and forth and you would absolutely feel that in the steering wheel.
I have done nothing to the front suspension on my car and did just about everything on the rear suspension, and every time i change a piece in the rear, i feel it in the front.
on a solid axle 11-14 GT i would agree and say there's no way it's the driveshaft. IMO, the IRS in these cars are genuinely the worst and best thing about them at the exact same time...

 

[noGreta!]

You sure it isn't the car tramlining at speed and you feeling it in the steering wheel?
A driveshaft issue is not going to show up in the steering wheel.
You got the lane keep system off. that shakes the wheel if it thinks you are drifting out of your marked lane?

Lane assist was turned off immediately during the test drive and left off for the end of time.

 

[RagmopInKona]

Lane assist was turned off immediately during the test drive and left off for the end of time.

I hit the button on the stalk somehow, and thought I had a blow out the first time it went off.
off it will stay while I own it. what a stupid system.

 

[noGreta!]

*update*

After putting the car on the lift and checking all of the aforementioned areas nothing stands out. I will be considering a custom DS in case I get lucky. Thanks guys.

 

[jmagnus87]

*update*

After putting the car on the lift and checking all of the aforementioned areas nothing stands out. I will be considering a custom DS in case I get lucky. Thanks guys.

So did you try running the car through the gears while it was on the lift? No throttle just idle speeds to let the tires spin freely? I'm thinking your issue is on the rear honestly.
also is this a performance park car?

 

[noGreta!]

So did you try running the car through the gears while it was on the lift? No throttle just idle speeds to let the tires spin freely? I'm thinking your issue is on the rear honestly.
also is this a performance park car?

I am afraid not; I was not allowed to do that (safety issues and so on...).

This isn't a PP car.

My mechanic suggested it is probably a inherent design flaw in the geometry of the DS that would go unnoticed by most people. It fits the online rhetoric that I am reading (there is a giga thread about this on this forum).

 

[jmagnus87]

Oh gotcha, like i can see scuffs and scratches that most people will never see on a car lol but i don't notice vibrations much to be perfectly honest.
My car with the 305 front tires definitely has a funny feeling to it especially through the steering wheel but yeah man get a nice driveshaft upgrade and let us know how you like it and if it fixed it!

 

[Cory S]

Fun question, did you try by any chance shifting into 5th from 6th and hit the same speed on the highway? Because that would either make it violently worse or smooth out like the OP said over certain mph as the driveshaft would be spinning at higher rates...

The driveshaft doesn’t change rotational speed when you are traveling at one speed when using different transmission ratios…..

 

[jmagnus87]

The driveshaft doesn’t change rotational speed when you are traveling at one speed when using different transmission ratios…..

This was already stated and i acknowledged that i was wrong in my thinking earlier in this thread. Please read the whole thing before commenting on something that's old news. I was thinking of it changing final drive ratio when it wasn't, but i was grasping at every single possibility hoping for any shred of something that might help the OP in his situation.

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