I got a problem with my 01 Blazer, there is a roaring noise in the front end while driving, it sounds like your typical wheel bearing noise. Also you can feel it a little bit in the steering wheel. Heres what I have done so far, replaced both front wheel bearings, replaced both front rotors and pads, rotated front tires to rear. All this stuff I have done has not made any change in the noise. Could C.V. axles make this type of noise, Im stumped, any help would be appreciated. My 2001 is 4-wheel drive, Thanks.

 

I'm sure one of the experts will chime in, especially if I'm wrong, but if it's really from the front then I'd start looking at the front transfer case as the axels are turning whether you're in 4wd or not. A common problem is the actuator under the battery that leaves a gear in 4wd...not a real hard or expensive fix from what I've read. There's also a slim chance that the new wheel bearing is bad. Usually CV joints just make a clunking or clicking noise when they go bad but that's one of the few things that haven't broken on my truck....yet.

 

That's funny - I just found this forum and joined today to research the same problem.

The noise seems worst between 45 and 60, and seems to lessen if you let off the gas, and come right back when you give it a little gas.

I was thinking transfer case....

I'm planning on getting rid of this vehicle after this winter - can it last for the winter?

Anyone else have this problem and know what the fix is?

Any input would be appreciated!

 

I have this problem as well on my 1998. Its also a 4WD but the noise only comes up in 2WD. I found that switching it into 4hi then back into 2hi gets rid of the noise until I accelerate from a stop. I'm stumpped as well

 

I did a search earlier on this and found two possible candidates - read quotes from search below:

"
Your front axle may be engage partially. Mine did something similar right after we got it. Crawl up under the truck and find the Transfer Case vacuum switch. It is located on top of the front of the T-Case around the front drive shaft, its not very big and has 3 Vacuum lines going to it. its like a 9/16 wrench. If you pull it out and the little ball is jammed up in the switch, it's bad; you should be able to see like a 1/4 to 3/8 of the ball"

AND

"The other thing I would check is the engagement sleeve gear. This is what engages the 4x4 and it is a loop with a fork shaft that the vaccuum acuator pulls into mesh. This gear is pretty indistructable but the gear it meshes with is pretty soft and can be stripped. This is kinda a big job but is not impossible. You don't have to take out the front diff to do it, and you don't have to pull the whole diff carrier apart to do this either. Somewhere ive written my experience on when that vacuum switch fails altogether. And the gear stripped completely."

Sorry forgot to see who originally posted. Hope this helps - let me know if it does!

 

What year Blazer are you refering to? That has this type of vacuum switch.

 

I also joined because of this problem...JUST noticed it leaving work today...driving very slowly, it sounded like the inner fender liner on the passenger side was rubbing the tire...the noise faded as I accelerated, but gets louder as I slow down. Reading on here, I tried taking a short trip, hit the 4HI button, and it went away immediatly. I rarely use the four wheel drive, and never except in winter. I'm hoping it's the actuator!!

 

And I found the cause of my noise!! Not the actuator, but a vacuum line...
My '98 is a manual, and I was checking the clutch fluid the other day, and noticed a hiss...there is a small tee loacted near the reservoir with 3 vacuum lines running of it...one going to something under the intake hose(not sure what it is called) another running through the driver front fender...long story short, just brushing these vacuum lines with my hand, made them disintegrate. So, went to the local auto parts store, and replaced the vacuum line. No noise up until today, checking everyting out caused me to think...the line running to the fender well seemed a bit big,when I replaced it, so I checked..it had fallen off!! Put it back on, took a drive, and no more noise! Now, just need a smaller vacuum line, lol!

 

I had the same problem with my 2000 blazer. Noise at speeds between 40 and 65. It was a grinding noise with a definite vibration that I could feel in the seat and with my feet on the floor. I thought of several things it could be. I started with a new set of front hubs, no change. Next I replaced both axles in the front. I used GM axles and I had the same noise. My only thought was maybe a bearing in front differential, so I replaced it, ( what a job) no change, noise still there. I was laying on the creeper looking at everything, and then I saw it. The front drive shaft. On the rear of the shaft near the transferr case it has some sort if c v type joint, I noticed a small hole in the rubber covering that joint. I touched the cover and dusty looking rust came out. I poked a oil can into the hole and pumped it with some good ole 30 weight motor oil. Test drive, the noise was a lot better. I removed the front drive shaft and the noise was gone. Now I am looking how to repair my drive shaft or replace it.

 

It's most likely your transfer case partially engaging. Do a search, there are a ton of how to articles for trouble shooting 4x4 problems.