I have a sound system too with a "box" in the rear and I also turn it up to not listen to that annoying whine. If anyone has an east coast contact and how much it ran them, that would be fine too.
Here is member, PBR's, thread/reply from 2003 but it looks like Isuzu took care of it at that time so it was no out of pocket for him/her.
http://vehicross.info/forums/showthr...ht=ring+pinion