2000 Blazer, Funny Noise

[blink325]

I have recently begun hearing an odd noise when I am accelerating and decelerating my blazer. To me, it sounds like a there is a moped underneath my car. I hear it coming from the back end. I have no idea what it could be, and I haven't taken it anywhere yet. I'm just trying to see if any of you have heard an odd noise like this and might know what it could possibly be. Thanks, and this is my first post!

[Jeremy Fitch]

Sounds like an exhaust problem, check for leaks or holes in exhaust. Sorry don't mean to laugh but never had anyone tell me a noise sounded like they had ran over a moped and it was stuck under their car before.

[mike2004tct]

You better go out and look under the truck to make sure it's not a China Man under there (Like in the movie "CRASH")

[blink325]

It really does sound like a moped . It doesn't do it when I'm idling, and the pitch seems to get higher the faster I go. Could this be a wheel bearing problem? I don't notice any significance when I make turns, just a constant humming/buzzing noise that sounds likes it's coming from underneath the car.

[blink325]

Quick Update

I just recently got in the car to drive to the store and the noise seems to be getting worse. I am also feeling a vibration in the steering wheel. On top of that, if I go to the the rear of the vehicle I can hear a buzzing coming from what sounds near the gas tank, or some part of the exhaust.

[mike2004tct]

Originally Posted by blink325

Quick Update

I just recently got in the car to drive to the store and the noise seems to be getting worse. I am also feeling a vibration in the steering wheel. On top of that, if I go to the the rear of the vehicle I can hear a buzzing coming from what sounds near the gas tank, or some part of the exhaust.

The buzz in the rear-end could be the fuel pump if you hear it around the tank while the truck is idling- probably nothing to worry about,yet.
The vibration in the steering wheel could be numerous problems; bad bearing, ball joint, half shaft, control arm, shocks, tire balance off,etc. None of these symptoms would relate to your original post (which sounds like a bad exhaust to me).
So it sounds to me like you have quite a few problems.
I think the moped noise is related to the exhaust (as stated above), the buzzing from the gas tank area probably not too much of a problem unless it becomes hard to start, the vibration in the steering wheel is a BIG problem. Please descibe if it's constant, or only when turning, or going over bumps, whatever.
Edit; One other thought here, you might want to crawl under the truck and look to see if you have a heat-shield above the muffler. This may have rusted off, and it could cause a buzzing noise.

[blink325]

Well the vibration just started, the noise has been there for a couple days now. I only feel the vibration, and the noise after I hit around 10-15 mph. The noise gets louder and the vibration more intense the faster I go. I slow down, they both dissipate.

[old_master]

Sounds to me like a universal joint, or possibly bearings in the differential.

[kb3jhp]

Originally Posted by blink325

I have recently begun hearing an odd noise when I am accelerating and decelerating my blazer. To me, it sounds like a there is a moped underneath my car. I hear it coming from the back end. I have no idea what it could be, and I haven't taken it anywhere yet. I'm just trying to see if any of you have heard an odd noise like this and might know what it could possibly be. Thanks, and this is my first post!

IF IT IS 4WHEEL DRIVE PUT IN 4WHEEL AND SEE IF ANY OF IT QUITS

[blink325]

Nope 2WD.

[bowhunter1432]

that happened to me last winter in my 2000 i had to replace both front hubs.

[corning_d3]

My '99 Blazer had the same problem.. After changing the muffler(loose baffles) and a few exhaust hangers(worn rubber), mine was nice 'n' quiet again..

[blink325]

Well, I had it checked out. It's wheel bearings on the back passenger. What's the average price for a job like that? I don't wanna get screwed

[corning_d3]

Are you positive it's a bad wheel bearing? You said the pitch didn't change when turning. When turning, the inside tire slows down while the outside tire speeds up. If it were a wheelbearing, the pitch would change. I'm gonna take a guess and say it's more likely to be a pinion shaft bearing or a differential carrier bearing in the rear-end going out, which is located inside the differential. The pinion and differential housing rotate at the same speed regardless of whether your turning or not, so the pitch would be constant around turns. A worn pinion bearing would also allow the driveshaft and pinion shaft to wobble, creating a vibration. If it does turn out to be the wheelbearing, don't expect it to be cheap. The parts are cheap(about $15.00), but it requires that the axle be partially dis-assembled, and some models have to have to bearings pressed on and off the axle shaft or axle tube..