So I finished installing an 07 ap2 diff into my 00 ap1 with a 4.44 FD from Motorklasse that was rebuilt. Fluid I'm using is Amsoil 75w90 severe gear oil. Under acceleration/coasting/turns it makes this hi pitched "sheering/shhh" noise. It doesn't happen all the time but it is intermittent. At first I thought it was the brakes because the noise disappeared after a few miles of driving but it returned later in the day. I'm thinking it maybe the fluid? or maybe its something I forgot to tighten down. If anyone has experienced this or knows how to resolve this, advice is much appreciated. Thanks

 

aftermarket gears whine...is that what youre hearing?

 

It sounds more like a metallic sheering sound vs a whine.

 

I have the same gears without any Whine, I Know a lot of people on this forum say they all whine and not to worry,
but as my gears dont whine, I dont think ignoring the noise is the best idea.

 

Does it sound like a brush rubbing against a rotating metal drum?

 

Yup

 

Having a higher carrier bearing preload will make that sound. In the few diffs that I've built, the sound went away when the preload was set on the lower end of the spec. I personally like aiming for a higher value but some ppl hate the noise.

 

well the noise is gone now, I double checked my brakes to make sure nothing was in it, drained and put new fluid in again and it seems to have gone away for now. Drove it again for a few miles and still no noise. I guess maybe it went away on its own?