Ya no… :). I was navel gazing and wondering if the resonant frequency of the arm was anywhere close to the driveshaft or axle speeds. :)

We need a real engineer like Stielow to weigh in… :). Or Donny likely has an idea on this.

Stielow is an FN988 guy as well in his latest build.

I believe they tossed around a few ideas at Donny's shop. Ultimately it would have been a trial and error and see what works thing. If he does think of something to try, I'd be all for it.

I would not go Speedtech for the rear again. Go Detroit Speed. The front is another story.

Donny, if you have both the 9" and FN988 can you post a side by side? Interested in how much more aside from the pinion support would have to be made to swap the 8.8 into the Speedtech torque arm.

Are the bolting locations in the same place (distance) from base of the housing?

That really sucks, I have a 9" with 3.70 gears, luckily I don't have any noise
. Looks like I might need to be in the planning stages for tunnel mods.
Thanks for the responses and info.
Hopefully you figure out the noise.