Car is 2002 Grand Prix GT 3800...not a f-body I know but I figured someone here might have some clues on what I should look for. Now my story that I already posted on my GP forum but no help yet.

So I was driving straight coming into town (no bumps etc..) and all of the sudden it sounded like a hammer banging really loud from my front end. Pulled over to look for any damage saw none so drove to the closest garage, when I got there the mechanic took a quick look and said it might be motor mounts, fine. So I drove very slowly to the shop I take my car to, didn't make the nose while driving slow (in between 40kph / 60kph) Got to the shop and my mechanic took it for a spin No noise what so ever!!! And has been fine for about 2 weeks now!!

My question is what would make it sound horrible?? something defiantly needs fixed!

I had my Wheel Bearings replaced about 1.5 years ago and they need doing again but I'm sure that was not the cause of this noise. I'm thinking Outer tie rod ends or possible motor mounts.

Is there anything else I should check for?? I read somewhere about a cracked sway bar making a similar noise...Car is still being driven daily, now and then I'll hear a slight clunk but nothing compared to the first time!!

Any input would be greatly appreciated!!

Cheers Scotty

I was thinking motor mounts,did your regular mechanic check them or just test drive it?

Its easy to see if tie rods are loose or you have a broken sway bar. Put it up and have a look. Wheel bearings can also be checked for play and spun for noise.

My Mechanic put a pry bar on the mounts and pried on them a little bit and said they seem fine, but I'm pretty sure you cant check them that easily. Car has always made a snap noise going into Drive or Reverse and I'm almost %100 its the motor mounts but my mechanic keeps telling me that the fine

What do I look for if a tie rod needs replacing?? Just if the tire has a bit of play??

Finally going to start doing all the work myself because nothing ever seems to get fixed at the shop, cars always on best behavior there

Jack up the front of the car and grab onto one of the front wheels.

If there is play right/left in the wheel then it is likely a tie rod (although given your description of the issue...I doubt it's a tie rod) Usually if it's a tie rod the rubber boot around it will be torn as well.

If there is play up/down then it is likely a balljoint (I've had a lot of weird symptoms from balljoints, so this is possible IMO)

Play both ways could mean a worn wheel bearing.....again, given your description, I doubt it.

Engine mounts are tricky....Does the car tend to "shake" when your transmission is in D and your stopped at a light? Sometime people have someone sit in the car with it in D apply a little gas.....If you see the engine "rise" a lot, then you could have a broken engine mount....trouble with that method is determining how much "rise" is too much.

Swaybar should be obvious....Locate it (I think it runs behind the engine in the GP?) and check to see if the links, mounts, or the bar itself are broken.

I highly doubt its a motor mount. The mounts are under load when accelerating not when driving/coasting. All you can do is check for worn parts unless it makes the noise again. Hell it could have been a chunk of rust coming off the edge of a rotor.

Thanks guys!! Will check it all out as soon as I have time to get under it! hopefully tomorrow morning