Mysterious vibration in '01 Blazer

HI everyone

I have an '01 Blazer that’s had a strange vibration for some time now. Here are the particulars:

  • It’s a low frequency rumbling
  • It happens only between 45 and 60 mph
  • It tends to come and go
  • It usually starts after about 5 minutes of driving first thing in the day
  • It generally goes away after awhile and may not happen the rest of the day
  • It happens only when I’m accelerating or maintaining speed on an incline
  • It happens when it’s hot, cold, wet or dry

What I’ve done lately:

  • replaced all the brake pads
  • replaced one rear rotor and caliper slide pins (one pin was frozen and the rotor was badly worn)
  • Checked the U-joints, which are sound

Any ideas?

I’ve seen rumbles like that disappear after I replaced one of the halfshafts but you checked the u-joints. My experience wasn’t with a Blazer, though
How old are the U-joints? Are they original?

Wheel bearings are my number one guess. If you pretend you are at Le Mans and do aggressive left and right turns while the noise is happening, and the turns effect the sound I would get the wheel bearings checked. A stethoscope can be very handy, not while driving of course.

RemcoW - I would guess the U-joints are original, but I couldn’t get them to budge at all when I shook the driveshaft.

Barkydog - The thing that doesn’t make sense to me is that the vibration stops as soon as I let off the gas. Do you think the bearings would respond to that?

I have had 2 front wheel bearings go out under different conditions. Yes I think it is a possibility, if not I would not have posted.

Both front bearings on my Blazer went bad after I bought new tires. I thought the noise was from the new tires. I don’t recall any vibration. The noise changed when the steering wheel was turned off-center (i.e. changing lanes or turning).

I had a vibration at 60-65 mph in my wife’s 98 Ford Windstar. The lug nuts on one tire were coming loose a month or two after I changed the tire after a flat.

Ed B.

OK, thanks guys. I’ll def check the bearings.