I've been chasing a noise that sounds like its coming from the front differential. Basically its a "hum" that seems to show up at about 40mph coasting thru right turns. Well, with the snow today, I had the noise pretty much continuously with 4x4 hi engaged. I'm thinking the front differential needs a bearing or two. Anyone have recommendation near Bethesda or Chevy Chase (Montgomery County)? Thanks.

 

Do you have auto or manual locking hubs? Just trying to narrow down if the whole axle is turning or just the hubs. How many miles?

 

The truck has about 91k on it. It's a '97 with the 4x4 shifter on the floor (not electronic). As far as I know, the hubs engage automatically (in the front differential) when I throw the lever. I'm sure that the 4x4 is engaging, checked it in the snow last night.

 

Sounds like a bad wheel/hub bearing.

 

That's exactly what I thought. But, I've changed both front hubs and both rear wheel bearings. There was a post in the '97-'03 section that sounds like the same noise I have and the guy is pretty sure it's coming from the front differential where the CV shaft flange mates to the diff flange.