Loud humming/roaring from front left side
 

I've had my '98 S10 Blazer 4X4 for 3 years now and and about 9 months ago it developed a humming noise from the front end. Replaced all four tires, brakes, rotors, all shocks. Checked wheel bearing assemblies, u joints, all three fluids-rear end, front end, and transfer case- all OK. The roaring has increased and is now vibrating the steering column while on highway. Does anyone have any ideas?

My mechanic friend found a minute dry-rot crack in the left outer cv boot of the left half shaft with a very, very, little amount of grease around the crack. Could this roaring be coming from the left half shaft? Any ideas. Savings is deleted from replacing fuel pump, alternator, various other mechanical failures.

Help!

RE: Loud humming/roaring from front left side
 

Did the noise begin before or after you replaced the tires?

RE: Loud humming/roaring from front left side
 

Before. I replaced all four tires thinking that was the problem, but it continued and has gotten louder since.

RE: Loud humming/roaring from front left side
 

The noise and vibrating probably has something to do with the crack in the cv boot.

RE: Loud humming/roaring from front left side
 

Any question, This past January, my friend mechanic found the front pumkin almost 1 quart low in oil. He filled it to the sight plug. Could it be that a bearing could have "spun" in the front housing causing this noise? How likely would this be?

The cv boot crack is so minute it has a slight potential of being dry.

RE: Loud humming/roaring from front left side
 

Might be a bad bearing somewhere. I'm no specialist since I've never worked on a 4wd, I've never heard of a pumkin, unless you have one during halloween. I know very little about 4wd's. Might have to wait till tomorrow when the people who know something about 4wd's on blazers are around. Almost any question on a motor, and I'll have the answer.

RE: Loud humming/roaring from front left side
 

pumkin - front differential I guess - kinda looks like a pumkin - language used by my mechanic friend. Anyway this is really weird though. The roaring stops when I turn left, but when I drive forward or to the right, it roars. Thanks for your responses, really appreciate it. I just don't want anything to break or fall off when I'm driving. That would be my luck.

RE: Loud humming/roaring from front left side
 

Oh the front diff. Yea, I know what that is. Is the right type of oil being used?

RE: Loud humming/roaring from front left side
 

Yes. A parts guy just called and said he heard about this problem another gal had. He's going to look it up, but said he's positive it was the same circumstance. Something totally in a different direction. Speed sensor or something. He'll look up the job and call me tomorrow from his work. I guess I'll wait for his call, but appreciate your help. I'll post the solution tomorrow night if your interested in what he says. I don't know if he'll have the exact solution, but I can't afford to go replacing everything doing the process of elimination thing.

Have a great night!

RE: Loud humming/roaring from front left side
 

I had this problem as well. Last year or year before and mine ended up being the wheel bearing. Best thing to do is lift your vehicle on that side and see if the tire is wobbly. But I would be thinking that is the issue. Is it pulling any?