Gears & Axles - Vibration and whine with rearend install

Got my 9" rearend installed. first thing i noticed is this thing whines and howls a lot, will that go away as the gears get broke in? I'm sure noping so.

Also there is a vibration which i assume is the driveshaft. I installed a new u-joint on the rearend side and left the stock one in the tranny. But it was good and turned free. I am reusing the stock drive shaft for now as i will be changing tranny hear shortly and didn't want to order another driveshaft when that happens as well.

My question is, what is causing the vibration? I have read it could be the pinion angle, but i'm not really sure how to check this. where do you measure the angle of the rear end at? I put my angle finder on the torque arm mount, but i don't think it is parrallel with the center line of the pumpkin, and there aren't really any flat surfaces to attach it to. (this is a quick performance rear end)

First, if it's whining and howling, it was most definitely set up improperly and the noise most likely will not go away.

Second, to measure pinion angle you want to measure the difference in angle between the rear end at the pinion, and the driveshaft. put your angle finder on both. If they both read the same angle, you are at 0 degrees. Most people run their pinion angle at -1 degrees.

at -1 degree's you mean that the angle of the rear is down 1 degree from the angle of the drive shaft?

why would 0 degree be bad? you'd think that would be less vibrations and isues as the u joint will barely have any movement at all...

at -1 degree's you mean that the angle of the rear is down 1 degree from the angle of the drive shaft?

why would 0 degree be bad? you'd think that would be less vibrations and isues as the u joint will barely have any movement at all...

Yes, you want the rear angled down from the angle of the driveshaft by -1 to -2 degrees. Under any kind of load the rear will rotate up to 0 degrees.

The vibration could be from the driveshaft not going far enough into the tailshaft of the transmission. I have had this be a problem for several customers, as a nine inch should really have a one inch longer driveshaft. Bob

I actually have a similar issue with vibration. I was assuming it was u joints but havnt been able to check it being the clutch was slipping before now with the new one its still vibrating at highway speeds. It's really annoying. Let us know how you make out. I have a nodular center all new bearings in a fab 9 with strange drive shaft.

Make sure the rear U-Joint is all the way in the rear end's yoke.

Al 95 Z28

the biggest problem when people buy new rearends are they dont get them checked before installing to make sure its setup correctly,common mistake!!.id take it to a professional shop before putting in my car!!