Thread: Strange pulsing/thumping sound no one can figure out...

I have a strange pulsing/thumping sound coming from the front end. It is there no matter how fast I am driving and the rate of the thumping sound seems directly tied to the speed of the tires. I have summer tires/wheels and snow tires/wheels and the sound is not affected by changing either set of wheels/tires (that was my first thought because it seemed like a wheel that was horribly out of balance or something. However, when I've had out of balance tires, you feel the vibe more than hear it. This is the opposite - you hear it more than you can feel it, and if you do feel it, it's felt more in the gas pedal, but also slightly in the steering wheel). The thumping sound is loudest at about the 40 MPH speed, but that could just be due to decreased road noise vs being at freeway speed. Also, the thumping sound is not affected/changed by accelerating or braking.
I couldn't find any play in the steering so I took it to a mechanic to see if they could figure why my car sounded like a helipcopter sometimes. They took it for a drive, could hear the sound, but got it up on a rack and couldn't find anything wrong - steering/suspension seemed tight. They said it sounded like an issue with the tires - I later put on the winter tires/wheels and no change whatsoever.

I've changed my lower motor mount within the last couple years, but my trans mount is the factory one. I've checked out the trans mount visually, and while it looks old, it is in tact and doesn't seem to have anything "wrong" with it. Could a bad trans mount cause my issue?

Can you all think of anything else that could possibly do this? I'm at a loss...


For what it's worth, I do get weird, sporadic, possibly unrelated clunks at acceleration, deceleration, or sometimes on a turn. I've done the dog bone mount flip and the bushings seem fine. Again, the lower motor mount has been replaced with a solid rubber mount.

Thanks y'all.

Ok, I'll check out the CV's and see if that leads to anything.

When my last CV axle went bad it would shake the car pretty hard but only around 35-40 MPH. Also, the car would be completely silent/shake-free if I was coasting. The problem I have now is present no matter what speed I'm at or whether I'm braking or gassing it. I guess maybe the inner or outer joints of the CV could produce different symptoms?

Replaced the passenger CV axle and that had no affect. I'll change the driver side next week and hopefully that solves it.

Well, I REALLY hope that is not the case for me.

Well, both axles are replaced and nothing has changed.

What's the next mostly likely, cheapest, easiest to diagnose thing I can check next? haha

I've never done anything with a flexplate or harmonic balancer before. Are there any good write ups or more info on those?

Originally Posted by Deviq

is it possible that a bad wheel bearing could cause this?

I had a friend listen to the problem and he thinks it's a wheel bearing. I've checked both wheels for play at 12 and 6 o'clock and they're rock solid.

Is it possible for a wheel bearing to go bad but have no play in it? If wheel bearings weren't so stinking expensive I'd swap one in just to see but $100-$120 is expensive for a guess.

Raise the car up and grab hold of the spring on the strut or where the tie rod bolts to the knuckle and spin the tires as fast as you can, feel for a vibration/grinding.

That's a good idea. I'll give that a shot.

You guys were right! Driver wheel bearing/hub! Put a new timken hub on and all the sounds are gone. Thanks for the help guys!

Glad its fixed.