Hello! so I just rebuilt my 9 bolt with all new bearings and got It in the car. I just noticed after a few miles that there is a subtle whine when ACCELERATING ONLY. I think it's in my rear end. Any ideas? I read that it could be a pinion bearing but it is new.. maybe it's because of the new shimming I did to the carrier? I'm also uncertain of my smart crush sleeve.. I installed it to proper pinion preload but I had forgotten to install my pinion seal.... unable to obtain another crush sleeve I removed the pinion nut installed the seal and did my best to obtain proper preload again. I feel like this could be my mistake lol. but I still got a good preload, I do have a feeling though that the preload may have loosed up though. (its my first time rebuilding a rear end, please excuse my inexperience.)

You probably need to get another crush spacer and try the pinion bearing preload again. Did you change the backlash or pinion depth when you put it back together?

thats what i was thinking, just dont want it to blow up on me. same pinion depth but i set the backlash to .008. i have no idea what it was before.

That might be a little too tight for used gears. I'd go closer to .010 or .011. Increasing the backlash might fix it without having to do anything else.