I get a slight wine from My 8-1/4", non-posi, with 2.76 gears. - My friend tells Me, that He has had several , of these, and they all did it. -- Any body else ??
I get a howl out of my SG 741 3.91 s. It's louder on acceleration and quiets on deceleration. The gear teeth contact are within specs. Probably a pinion bearing.
