I have a strange noise which sounds like its coming from the rear differential or a wheel bearing. I can't tell. It's not consistent and usually happens above 50km/hr. Engine and transmission run great, no vibration, shifts smooth, absolutely no issues. Happens in neutral as well and doesn't change during acceleration. The only way I can describe the sound is it is similar to driving over those tar repair lines on the road, or driving on gravel. Not a grinding. No vibration in wheel or the drive itself, just the intermittent noise from the rear.
The recent service that was done was an alignment and a rear diff change. Used same spec oil but Amsoil brand. The car has 208 thousand km (129 000 miles)
Jack up the wheel and rotate by hand to see if there is any roughness or noise discernable. You could also try a noise-finding gadget like the ones Scotty has demonstrated:
https://www.youtube.com/watch?v=Wy5nqh3LSs4
