The car has a zexel torsen HD posi with richmond 4.10 gears. They were all installed 3 years ago. At the same time new axles, bearings and a summit rearend cover with the preload bolts. The drivline and ujoints are also new. I am also using amsoil synthetic. Has anybody ever had the problem where under no load the rearend will make a faint grind. If the car is speeding up or slowing down ,even a small amount, the rearend grind stops. Even pulling down the straight interstate is enough load on the gears to make them quite. If the car starts off a slight incline where there is no load on the gears it starts to growl a little at me.
I pulled the cover off today and everthing looked fine
Any idea what it might be?

I had an 86 that would growl at me only in reverse but I believe it was because I got it stuck off road in the dirt and the posi got damaged when i was trying to get her out, but she only did it in reverse.

I have never set up a rear before so I dont know, Would too much backlash cause this? I dont want to sound like a idiot but is like the gears need to mesh more. It does not make any noise if the gears are touching. If the car is slowing down or speeding up, even slightly it does not make the sound. Only when the gears kind of float inbetween speeding up and slowing down,

Well it only made the noise in reavers turning I seam to remember now so it had to be the posi