• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

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

SliceTheRice

SliceTheRice

New member
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.
 


check your flex plate/torque converter they make a pretty good clunking sound when they go bad... maybe harmonic balancer, put a video on youtube and post a link here and we can go from there
 
upon re-reading your post and seeing that it clunks while turning, im probably gonna have to possibly agree with buggsy and say check your cv first then check flexplate/tc
 
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.
 
I have seen a case where the reluctor wheel on the differential move enough to contact the diff. housing and cause a clunk on each revolution.
 
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?
 


Deviq said:
is it possible that a bad wheel bearing could cause this?
Click to expand...

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.
 
I agree with deviq. I had nearly identical symptoms to you about a month ago, it ended up being my passenger side wheel bearing. I found out by doing what fivefingerdeathpunch suggested, that method worked rather well.
 
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!
 


You must log in or register to reply here.
Back
Top