Hi folks. I have a 2004 4x4 2dr Blazer (3 button switch) 4.3l and been getting a loud humming noise, no clunking or banging though.

As I accelerate the humming gets louder and sharper as apposed to deceleration were it gets deeper. The humming comes at about (constant after 50km/hr) 40-50km/hr and stays even if I release acceleration, until a point were speed drops below above stated. No difference in the sound of the humming if I turn the wheel back and forth while driving to shift the weight from side to side, so I am not sure if it would be a wheel bearing (which I hear the blazer is infamous for) or some other problem.

Been told it is a pinion bearing problem, a u joint problem, a carrier bearing (which I am sure my blazer doesn't have as the shaft is way to short). I am pretty sure anyone who looked at it gave me a different answer, lol.

Any suggestions as to how I can narrow my problem down further. Thanks

Darryl

 

Does it matter if you have 4wd engaged or not? Have you checked the u-joints in both the front and rear driveshafts?

 

mines doing the same thing, but if i drive in 4 hi it goes away or doesnt do it... any ideas?

 

4wd Front Axle Clicking When in 2HI - Goes Away when in 4HI/4LO

Tech Article (DIY) Index FTW!!

 

so what do i do to fix this??

 

Click the link, read, then prepare to get your hands dirty. It isn't going to fix itself.

You have to get in there and figure out why it is not fully releasing.

 

Happens if 4x4 is engaged (hi or low). The u joints are rusty, but i could find no up or down play in either front or rear shaft, there is some backlash when spinning the rear shaft, I would guess about 1/8th to 3/16th play when I initially spin the shaft back and forth.

 

Turned out to be a wheel bearing after all.

I diagnosed it by jacking up the vehicle and used 4 jack stands for support. Had a friend press the accelerator while i used a steel bar to stop the drivers side front tire from spinning there by hearing the other bearing. Sure enough, that was the faulty bearing.