vibration at 50mph+
06-30-2008, 03:15 AM
#31
3rd Gear Member
Join Date: Nov 2005
Location:
Posts: 681
RE: vibration at 50mph+
ORIGINAL: dschmink
Well here's the update... at 50 it's just wheel shimmy. 60+ on cruise control theres a slight vibration when it decels slightly. Wasn't doing that yesterday. What. The. F@#K
Well here's the update... at 50 it's just wheel shimmy. 60+ on cruise control theres a slight vibration when it decels slightly. Wasn't doing that yesterday. What. The. F@#K
Dragon Stang, as for the pinion angle changing, it happens sometimes with the removal and re-installation of the DS and driving it, something could have been thrown off slightly and could simply need adjusting. In addition, balance and precise accuracy is necessary to ensure no vibration especially at higher speeds as the rotations/revolutions per minute increase significantly and an improper balance for example even if only barely off will compound itself with the centripetal acceleration of rotation. Acceleration and deceleration both apply a very different force upon the driveling dependent upon the directional torque applied to the ground and transferred through the Diff/Driveline/DS. That is why it seems it could be pinion: the DS does change angle between acceleration and deceleration. The force from the acceleration transfers the weight to the rear of the vehicle applying more load on the rear springs and the angle is obviously not going to be the same as when it is under deceleration. With this angle change, the rear pinion angle could be on spec while the front trans flange angle could be slightly off causing a decel only at certain speed when the angle seems to come into significance in being misaligned.
With that, I would assume that the faster you travel up to greater speed and then decelerate, the greater the vibration would be... is this right dschmink.
06-30-2008, 11:32 AM
#32
2nd Gear Member
Join Date: Sep 2007
Location: Michigan
Posts: 315
RE: vibration at 50mph+
ORIGINAL: Stang Skeleton
The vibration upon decel does suggest a DS/driveline issue. I can't see it being anything other than an unbalanced DS or a slightly off pinion angle. You should also have your wheels balanced at a local tire shop. Shouldn't run you more than 5-8 bux a wheel to balance and remount.
Dragon Stang, as for the pinion angle changing, it happens sometimes with the removal and re-installation of the DS and driving it, something could have been thrown off slightly and could simply need adjusting. In addition, balance and precise accuracy is necessary to ensure no vibration especially at higher speeds as the rotations/revolutions per minute increase significantly and an improper balance for example even if only barely off will compound itself with the centripetal acceleration of rotation. Acceleration and deceleration both apply a very different force upon the driveling dependent upon the directional torque applied to the ground and transferred through the Diff/Driveline/DS. That is why it seems it could be pinion: the DS does change angle between acceleration and deceleration. The force from the acceleration transfers the weight to the rear of the vehicle applying more load on the rear springs and the angle is obviously not going to be the same as when it is under deceleration. With this angle change, the rear pinion angle could be on spec while the front trans flange angle could be slightly off causing a decel only at certain speed when the angle seems to come into significance in being misaligned.
With that, I would assume that the faster you travel up to greater speed and then decelerate, the greater the vibration would be... is this right dschmink.
ORIGINAL: dschmink
Well here's the update... at 50 it's just wheel shimmy. 60+ on cruise control theres a slight vibration when it decels slightly. Wasn't doing that yesterday. What. The. F@#K
Well here's the update... at 50 it's just wheel shimmy. 60+ on cruise control theres a slight vibration when it decels slightly. Wasn't doing that yesterday. What. The. F@#K
Dragon Stang, as for the pinion angle changing, it happens sometimes with the removal and re-installation of the DS and driving it, something could have been thrown off slightly and could simply need adjusting. In addition, balance and precise accuracy is necessary to ensure no vibration especially at higher speeds as the rotations/revolutions per minute increase significantly and an improper balance for example even if only barely off will compound itself with the centripetal acceleration of rotation. Acceleration and deceleration both apply a very different force upon the driveling dependent upon the directional torque applied to the ground and transferred through the Diff/Driveline/DS. That is why it seems it could be pinion: the DS does change angle between acceleration and deceleration. The force from the acceleration transfers the weight to the rear of the vehicle applying more load on the rear springs and the angle is obviously not going to be the same as when it is under deceleration. With this angle change, the rear pinion angle could be on spec while the front trans flange angle could be slightly off causing a decel only at certain speed when the angle seems to come into significance in being misaligned.
With that, I would assume that the faster you travel up to greater speed and then decelerate, the greater the vibration would be... is this right dschmink.
Now, if neither a torque stick or torque wrench is used and only the typical impact gun is used to install wheels, it can cause stress warping of the rotors which will setup vibration that can be felt in the steering wheel. Most times, a DS issue will be felt in "the seat of your pants" so to speak. That is, a distinct chassis vibration. Not in the steering wheel.
I would be very surprised that pinion angle changes would occur unless there are some excessively worn axle mounting parts are involved.
06-30-2008, 11:41 AM
#33
3rd Gear Member
Join Date: Mar 2008
Location: San Jose, California
Posts: 966
RE: vibration at 50mph+
The driveshaft vibration you're speaking of Stang Skeleton would not be felt in the steering wheel. I know because my first GT, an 06, had an out of balance driveshaft issue. It kept happening because they said there was a factory defect with the DS mounting points, stuff I don't know a lot about. All I know is that when I felt the vibration, it was in the chassis of the car, almost like a bumpy road but much more subtle. It was not in the steering wheel much if at all.
06-30-2008, 11:53 AM
#34
3rd Gear Member
Join Date: Nov 2005
Location:
Posts: 681
RE: vibration at 50mph+
Dragon Stang and xxDerek, yes didn't notice that it was solely steering wheel vibration. I though it seemed like the OP said there was steering wheels shake, but also vibration from the car on decel. If it is only from the steering wheel, then yes it is likely just the wheels needing to be balanced. Didn't catch that about it only being in the steering wheel 
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