ok.

03 GMC sierra 4x4 5.3 4l60E
148k miles

so the other night when I was driving home the truck started to make a low pitched grinding noise from, what best I could tell, was the front end.

It does it at 10mph or above, does not change when I put it in 4wd, does not change when in neutral rolling down the road, does not change when turning either way, and does not change when braking.

I am suspecting either front the u-joints or the pinion bearing.

Could it be a wheel bearing or cv joint? I thought if it were one of these it would change the noise when turning to one side or the other.

Thanks for any advice!

 

Hub assemblies/bearings don't last very long in these things. Would be first place I look. I had to replace mine at 75K miles.

 

Ditto....I had to replace one of mine at 50,000 miles.

 

wow. now the noise is way more pronounced. its grinding, vibrating, and popping every once in a while. I think u-joints but I could be wrong, I am gonna crawl underneath it and take a peek.

how would I check for a bad wheel bearing?

 

if the vibration gets worse, then i say u-joint. i too had to replace one of my front hubs not long ago. mine had a bad abs sensor FWIW.
the best way to check the hub is to jack up the front, put the truck (and 4wd) in neutral, and spin the front wheels.
taking the wheels off probably wouldn't hurt

 

well my mechanic buddy told me it was a wheel bearing. I am going to replace that one and see if it fixes the problem.

Thanks for your help guys!

 

update: well you guys were right.

right front wheel bearing was blasted. oddly enough this is the first one that i have seen fail that didn't make a change in noise when turning.

but whatev, life goes on. truck drives great now.

 

Told you so! Yeah...They don't really change in noise when turning. They just sound like a freight train going down the road. Glad you got it fixed.

 

the front wheel bears go on these things?? the duramax in my 4th truck of this NBS style and have never had to change one yet i always ruin tie rods like normal bet i have bought 10 in past 5 years