If you have driven many miles since the seal was changed, a new wear pattern could have developed on the pinion and ring gear. In that case, the noise may not totally go away but may improve. If you have a small pointer type torque wrench capable of reading about 7-14 inch pounds which is a typical spec without a new pinion bearing , you can check it yourself. You will need to disconnect the drive shaft and remove the calipers (or drums) so that they don't affect your preload reading. If you applied too much torque to the nut where the preload is too high , The differential will need some disassembly to install a new crush sleeve prior to setting the preload.Truck started making a noise maybe 6k miles ago or so just guessing. Is it possible that if I have someone properly set the pinion seal nut now that it would prevent further damage?