Hi all, I have a 04 1500 QC with the 5.7L that has 48,000mi. I have recently started to get a humming noise while driving. It seems to start being the most noticeable around 40mph and seems to get louder with speed. I can also feel a vibration from this noise. My guess was the dreaded rear end issue with the LSD maybe? The best way to describe the noise is it sounds like humming from mud tires which sounds like its winding down when coming to a stop. I just had new tires put on and a alignment thinking it was my worn out tires but it still does this. Thanks for any info you can give.

 

Sounds like a good time to pull the rear diff cover. If nothing else it forces you to change the lube (never a bad thing), look for any metal pieces or shavings, run your finger inside the bottom when you've drained it. If it's the "C-Clips" you'll know right away...

 

Well, I had my mechanic take it out today and turns out just a bad left front wheel bearing thats causing it. Funny the tire shop never noticed this even after doing a 4 wheel alignment. I suppose this would also attribute to the inside edge wear on my old tires.. So for now it looks like its not the diff.