Nice let us know the results!

Would you suspect trans / differential - mount / bushing inserts to be a possible factor?

Stiffer bushing can only amplify a vibration issue. If there's no vibration with stock shaft, the culprit is the new driveshaft. With soft bushing the vibration is less noticeable, but it's there.

Yes but the bushings make a huge difference, especially if there is more than one type at the same time. I spent a couple hours researching this today across multiple platforms and pretty much all say that once you remove diff and/or subframe bushing *inserts*, the vibration either goes away or is drastically lessened.

I'm going to try removing the diff inserts (KDT925) next week and will report back. Hopefully it helps

Stock diff bushings did not help me. I am running solid subframe mounts though so that isn’t helping.


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I honestly have no idea; I just know how many units we have sold and how few complaints we have seen from vibration. To have two units have seriously bad vibrations at only 80 MPH, I think it's more vehicle-related than component-related.

Yeah apparently they raise the subframe and change the angle, which results in vibration, according to all these forums I read through anyway. Are you also having vibration at 80 mph?

I am running stock height settings with the solid mounts.

Mine is at about 105mph with mild resonance on decel around 65.


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Angles no longer have to line up with cv's
U joint driveshafts rotate in an elliptical with different velocity in a single rotation and the yokes have to be in phase.
CV= constant velocity

I understand the differences between the yoke types. I was asking if he could give any info as to why the company made the switch. He answered likely with as much info as he could put out for the company.

Took out the Whiteline diff bushings (KDT925) and briefly took the car up to 140 km/h (86 mph) and the vibration was vastly reduced. Gotta try it again for a bit longer, as this was only for a few seconds. Will update tonight

Take the 407etr at night. I don't feel anything even at 105mph (all OEM mounts/bushing) but most likely will at a higher critical speed. 2 piece stock driveshaft will be good to the speed limiter

Glad to hear it helped for you. I still have too much other shit bolted to my car I think is not helping.

Keep in mind I also have:

-whiteline subframe inserts
-perrin trans mount insert
-whiteline shifter bushing
-perrin engine mounts