This problem started yesterday and it's been reproducible ever since. Any time I start moving from a stop, there's a single muffled knock/clank sound coming from the bottom front half of the car. The issue happens whether I start off quickly or slowly (feathering the clutch). I think it only happens in 1st gear. I tried to start in 2nd gear to see if the issue is reproducible and I couldn't hear it (It could just be engine noise masking it).

It's a 2006 tC, manual transmission with ~60k miles. I change oil and rotate tires every 5k miles. I have not changed transmission fluid.

Has anyone seen this issue before? Any info/tip is appreciated.

Mods - Please move this thread if I'm in the wrong forum. Thanks.

 

my guess is something is loose. maybe check all of the exhaust bolts and anything around where the noise is coming from

 

I'm assuming the knocking isn't RPM dependent? Like, if you give more throttle while feathering out the clutch in 1st it doesn't knock any louder or more often?


I want to say it might be a worn engine mount, but theres alot of stuff it could be. Sucks that you're out of your 60k warranty.

Give some more info or possibly a video?


Also you probably should've changed your tranny fluid by now but I am pretty certain that the trans isn't the problem.

 

x2 exhaust

 

x3 exhaust


maybe tranny mount? or clutch?

 

check it out and get back to us....

 

Thanks for the replies, guys. I dropped it off at a dealership after work and before seeing this thread so I can't check it now.

The single knock after moving from a stop is not RPM dependent. However, if i really feather the clutch, the sound is less noticeable.

This afternoon, the problem extended to a constant knocking (sounds like a helicopter) once I'm at speed (+30 mph). It's also more noticeable if I let off the gas and start to cruise at speed (in and out of gear). There's also a slight vibration accompanying the knocks that feels like there's a flat spot on my tires. But AFAIK, there aren't any.

Sometimes, when rolling to a stop, there's a rattling and squeaking sound coming from the front of the car.

Once I see the car again, what do I look for in the exhaust system? Loose bolts?

Thanks again,

 

If you have a way of safely jacking up the car and letting it cool, you can slide under your car and sort of check things out with your hands to see if anything is looses.
Give a few small tugs in places around exhaust mounts and places the exhaust is bolted together.
Don't tug so hard you break something. You are just trying to recreate the sound you are hearing in the car. Look for lose bolts and other things that might be out of place.
Clean metal/parts not worn as much or over worn is could be a sign that something has changed.
I wish I could give you better tips. Good luck.

 

How loud is it exactly?

Slight tapping? or is it like someone is beating under the hood with a hammer?

 

Does it "knock" at all durning crank? I had a loose exhaust that knocked during crank too.

 

yea pretty sure its exhaust. lol

change your trans fluid btw. its more than overdue.

 

dou you have any aftermarket parts? my car had the same issue a while back and it ended up being my anti-fouler for my 2nd o2 sensor was loose, because i have a header.

 

I would think motor / trans mount. Had the same thing in another car before.

 

Sigh... :slits wrists:
Turns out, it's caused by loose bolts on the front wheel. I rotated them last Sunday and didn't tighten them properly.

Changing tranny and brake fluid. Thanks again, guys.

 

Omg...you fail.

 

hey at least your wheel didnt fly off....

but major fail...

 

You should probably let someone eles do that from now on, lol...

...it could've been slightly worse though, you could've put snow tires on the rear...

 

LOL. I was closest, somehow. I win

by the way I worked at sears a ways back and one of the kids finger tightened the lugs on some ladys lexus. It took her like 300 miles and a week to bring it back saying the car felt funny when hitting bumps/potholes.


I don't think she was ever told the truth, but it was funny to see all four wheels cambered in different angles from the lugs being so loose.

 

Wow^ That is bad.

 

Sounds like what happened to a friend of mine. He was talking to the guy working on his bronco, so the guy forgot to tighten the lugs on the left rear wheel. So another guy working at the shop took it out to make sure everything was all good after they did an alignment and it fell off.