Hey all,

So I have a humming noise coming from the rear of my 4x4 blazer. I'm almost positive it's coming from the passenger side. It only happens from 35-55 mph, below or above that, there's no sounds. The hum is VERY quiet, you can barely hear it with the radio on at a normal conversation level, and it's a little above a medium pitch.

The details, my Blazer is lowered 2/3, with blocks in the rear. The blocks aren't angled, but according to my angle finder, i'm running a 2 degree pinion (from what I understand 1-4 is the "safe zone"). This noise WAS present before I lowered the truck a couple of weeks ago but it was even quieter then it is now. The humming has gotten louder over the last couple of weeks. I've also changed from LT Wranglers to Lo Pro tires; the noise was there before and after the tire swap, so I know that has nothing to do with it. Rear calipers are in good shape, pads are almost brand new, but the E-brake system itself is in pretty poor condition. I thought maybe it was the e-brake rubbing or something, so when at speed and the humming noise is there, I applied the e-brake slowly. The humming was still there but the truck did start to slow down, so i'm pretty sure it's not the e-brake making the noise.

I'm thinking it's the axel bearing going, but a friend of mine doesn't seem to think so. What do you guys think? Axle bearing, pinion noise, e-brake? I just want to get an idea before I decide to tear the rear end apart.

Thanks!

 

Usually if its a bearing or pinion its more of a growling sound. I had the same problem with my blazer and decided to change out the axle bearings and its still there so im sure its the diff bearings. If its not binding, or popping, or anything you should be ok to run it like that. Its not to bad of a job to replace the axle bearings and fluid which I would do and it may fix your problem.