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Discussion Starter #1
My car has a drive train vibration at around 60 to 70 mph when loaded.
Only mods are subframe locking bolts and Swift springs and Cusco sway bars.

Anyone else have the same issue or could comment? Only happens when loaded for a long weekend or just alot of extra weight.

I am going to remove the Whiteline subframe bolts and put some rock salt in the back and see if the problem still persists. This has been going on for a long time but I can't be sure if it was the lower ride height or the bolts or something in the diffs I need to get fixed.
 

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Discussion Starter #6 (Edited)
Thanks for the replies. Definitely not a wheel balance problem. Car has 20000 miles. I use two sets of wheels, Stock STI/BBS and stock XT,s for winter. Does it with both sets.

Car only does it when accelerating, feels like a out of balance axle but goes away when I let off the gas. Kind of a harmonic thing.
 

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2017 VW Golf SportWagen 5MT
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It sounds like something that is rotating is causing this. I would not think springs, sway bars or subframe bolts could cause this directly. Keep us posted, I'm curious.

Stan
 

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It's possible the mounts for the rear subframe are worn enough that when you accelerate the subframe is moving enough to vibrate with the lockdown bolts? Not all that likely though.

I've been getting a similar vibe lately, and i'm thinking its either a CV on one of my front axles (when under load its vibrating and when theres no load on the cv its fine), or my powersteering pump is completely screwed up and its causing a slight pulsation in the steeringwheel/steering rack.

Other possibilities: wheel bearing (the extra weight could be putting enough load on it to make it deflect more than normal), something in the diff (possibly the ring and pinion, but I would expect to see it any time its accelerating) etc.
 

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I've bought a Forester 2007 with 38000 km on the clock recently. When I drive the car above 30 km/h, especially around 55-65 km/h, an annoying vibration from the front wheels comes through steering. I replaced the old tyres with four sets of new tyres plus wheel alignment and balanced the tyres twice. No change. I took the car to the Subaru dealer and they decided to change the front wheel axels, left and right. They did but no change. The vibration is still there. Could it be the powersteering pump that produces this vibration? Or front wheel bearings? Or engin/gearbox/.... mounts?
 

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Discussion Starter #10
Will I have ant trouble with Subaru on a waranty issue with after market sways ans Swift springs. Warranty on car runs out in august and I want this resolved.
 

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Do you have an exhaust on the car?

I'm not talking for warranty, but from an NVH standpoint. I'm onto a different theory, but require your answer first.

But no, I do not believe it is wheel balance. It sounds like you're possibly getting the harmonic of the engine, and propshaft aligned. Commonly refered to engine parting order boom.

Could potentially be resolved by shimming the center bearing on the driveshaft a smidge.
 

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Discussion Starter #12
Do you have an exhaust on the car?

I'm not talking for warranty, but from an NVH standpoint. I'm onto a different theory, but require your answer first.

But no, I do not believe it is wheel balance. It sounds like you're possibly getting the harmonic of the engine, and propshaft aligned. Commonly refered to engine parting order boom.

Could potentially be resolved by shimming the center bearing on the driveshaft a smidge.
No, I do not have a after market exhaust. I think you may be on to somthing, I would like to hear more. Thanks
 

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2018 Forester XT 6spd/8spd/Many Gears CVT
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Have you recently had brake work performed on the car? We have seen that some rotors that even though are brand new are not balanced properly and will cause vibrations. Even though it does not make contact with the road, it still rotates.

We had this issue with a popular brand name rotor that a customer had brought to us to install once. Once we replaced it with another brand name of rotor, that vibration was gone.

It is highly unlikely that springs and swaybars will cause any type of vibrations as you describe, it has to be something that rotates at that particular frequency to cause that.

Gary
 

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If it's a drone as much as a vibration, meaning you hear it as much as you feel it, than it's likely engine parting order / propshaft boom. It can be a combination of exhaust, the way it is hung, propshaft angle, and possibly propshaft balance (though that's usually felt all over).

And if the above mentioned drone seems like you can "tune it" in to a sweet spot by adjusting the throttle ever so slightly, it would indicate the above-so more.

Let me know if the above seems to be on track.
 

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Discussion Starter #16
Remove the lock bolts, and the problem will go away.
I did that, the vibration is still there. I really think it could be driveline angle. When the car is
loaded and squated down is the only time I feel it, also only under acceleration?
 

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2009 Outback XT-B 5MT
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CV angle isn't going to be an issue. There is enough plunge to be able to run fully parallel to the ground.
 

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And since it's a independant rear, propshaft should be pretty steady and independant of lowering the vehicle.

W/ that all said, I did pick up a smidge when I lowered w/ the F-STi pinks, and got a decent amount when I dropped a good amount w/ '04 take-off parts. So I'm not proof positive that the CV's don't add a factor when lowered, but it took a significant amount of change on my part to get some "hum." It's not enough for the wife to notice, but I was an NVH engineer for a period, so it bugged me.
 

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If it's a drone as much as a vibration, meaning you hear it as much as you feel it, than it's likely engine parting order / propshaft boom. It can be a combination of exhaust, the way it is hung, propshaft angle, and possibly propshaft balance (though that's usually felt all over).

And if the above mentioned drone seems like you can "tune it" in to a sweet spot by adjusting the throttle ever so slightly, it would indicate the above-so more.

Let me know if the above seems to be on track.
hi guys
i have a similar problem with my YMO4 SG5 i thought it was the exhaust contacting the bodywork somewhere but had it up on the ramps and nothing showing,it only happens under load up hills mostly and between 2000 and 2,500 revs,any ideas
 
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