2002 LS rattles in the middle-to-back when in [D] and at a stop...?

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LincolnLS_2013

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Wondering if anyone can take a guess as to what's going on. I heard this a little when I first bought the car in October, but didn't know how to reproduce the sound, and wasn't that frequent. But now after adding 5,000 km to it (it's at 93,500km) I think it might be more frequent.

When I'm stopped at a red light in D, there's a rattling sound coming from the underside towards the middle-to-back of the vehicle. When I'm driving, there is no sound, so only when I'm stopped. And when I switch to N the sound goes away too.

Guessing it might be something with the driveshaft, no?

I've scrapped a couple speedbumps in my day, so that may have had an impact.
 
Check for a loose heat shield or the brace that goes under the exhaust behind the cats.
 
If you put the car in drive, hold the brakes and press the gas do you hear the rattle? If so, might be the catalytic converter itself.
 
jjcool00 said:
If you put the car in drive, hold the brakes and press the gas do you hear the rattle? If so, might be the catalytic converter itself.
Click to expand...

Oh, you know what... could be. Today I saw a small liquid/oil puddle underneath that area. Does Catalytic Converter use some sort of liquid?

On the other hand, the sound is coming more from the back-end.

But I'll try what you suggested. That's just revving the engine, right? The car won't move when I press both break and throttle? :D
 
LincolnLS_2013 said:
Oh, you know what... could be. Today I saw a small liquid/oil puddle underneath that area. Does Catalytic Converter use some sort of liquid?
Click to expand...

No, the cat is a hollow tube with a platinum/paladium coated ceramic element inside. What you are most likely seeing is air conditioner condensation.

LincolnLS_2013 said:
On the other hand, the sound is coming more from the back-end.
Click to expand...

Sound can travel in strange directions. Don't think that sound is coming from where you think it is unless you can either triangulate on it or use some sort of isolator like a stethiscope or rubber tube.

LincolnLS_2013 said:
But I'll try what you suggested. That's just revving the engine, right? The car won't move when I press both break and throttle? :D
Click to expand...

It may move a bit, if you don't have the brakes pushed hard enough. Don't let anyone under or in front of the car until you have an idea what will happen. But yes, put it in drive to put the engine under load, then give it some gas with the brakes on.
 
jjcool00 said:
If you put the car in drive, hold the brakes and press the gas do you hear the rattle? If so, might be the catalytic converter itself.
Click to expand...

If I am holding the brakes, and pressing gas also, is the drive-shaft turning?

If I am pressing the brakes, and not pressing the gas but the car is idling, is the drive-shaft turning?

I think the sound could be coming from the "rear differential". When I hit the brakes, is the drive-shaft disconnecting from the rear differential? And so it might be that for some reason, it's not disconnecting enough, and the drive-shaft is still turning and scraping away at the differential... something like that? Or do I have no idea what is going on there.
 
Wow. You have some odd theories there.
As long as the rear wheels aren't turning, the drive shaft isn't turning. If the rear wheels are turning, the drive shaft is turning. It's as simple as that. Doesn't matter what gear the transmission is in, brakes on or off, gas on or off.
There is nothing in the differential to disconnect the drive shaft. It is a permanent connection. The transmission and torque converter "disconnect" the drive shaft from the engine.

Just to be clear. In all of your examples above, if the car wasn't moving, the drive shaft wasn't turning.
 
Lots of good info here.


Rear-Wheel_Drive.gif

Rear-Wheel_Drive.gif
 
LincolnLS_2013 said:
That's just revving the engine, right? The car won't move when I press both break and throttle? :D
Click to expand...

for the record, they said give it SOME gas, not a lot. usually just enough load to get the rear to start to squat down a tiny bit would be ebough

if you give it too much gas, you could drive it right through a wall...
 
joegr said:
Wow. You have some odd theories there.
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Heh, thanks for the explanation. Yeah I wasn't sure how that bit operated.

Will give it a shot again the next time I'm driving.

So that means it can't have anything to do with the rear of the vehicle, the sound has to be travelling from the front.

Could be transmission or torque converter. The sound really depends on the speed. If I just stopped from a 70 km/h road, the sound is much worse than after moving on a slow road. And then while stopped, if I switch it to Neutral for a bit, and switch back to drive, the sound goes away -- not until I move and come to a stop again.
 
Curious as to why you are ignoring the possibility of it being exhaust related? Rattles from the exhaust system are often responsible for the symptoms you are relating.
 
joegr said:
Curious as to why you are ignoring the possibility of it being exhaust related? Rattles from the exhaust system are often responsible for the symptoms you are relating.
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Actually, I was thinking that just the other day. Could definitely be the exhaust.
 
Could the issue be caused by the bushings?

Also, anyone know what has to be taken apart to get at these bushings? 1 hour each, or more?

AjCRPya.jpg


m1nxDq9.jpg
 
You have to replace the rear toe links. There's a big thread on here about them. There's no separate bushing that you can replace. Be warned, you have to replace the hardware too (nuts and bolts), and you'll want to do a four wheel alignment right after they are replaced.
 
This is that LS that drove half across Canada with the loaded trailer, correct ?
 
Yeah you need new toe links, but that is not related to the problem you were describing.
 
joegr said:
You have to replace the rear toe links. There's a big thread on here about them. There's no separate bushing that you can replace. Be warned, you have to replace the hardware too (nuts and bolts), and you'll want to do a four wheel alignment right after they are replaced.
Click to expand...

Holy sh**, is this supposed to be connected somewhere? That tie rod is snapped in two, right? (Can you link me to a seller that has the rear toe links, can't find them anywhere)

mE3aXCd.jpg


BigRigLS said:
This is that LS that drove half across Canada with the loaded trailer, correct ?
Click to expand...

Yeah. I took it to mechanic before the trip and this is was what he found. Need new bushings before the trip, and tie rods too.

How essential is that tie rod -- should I stop driving until I get that replaced? I asked the mechanic before the trip if there's anything I needed replaced immediately, and he said no, I can do all of it after the trip.
 
That's the link to the rear anti-sway bar. What does the other side look like? I'd really want the anti-sway bar to be there and to be connected on both sides.
(It's not a tie rod. You'll confuse everyone if you call it that.)
 
joegr said:
That's the link to the rear anti-sway bar. What does the other side look like? I'd really want the anti-sway bar to be there and to be connected on both sides.
(It's not a tie rod. You'll confuse everyone if you call it that.)
Click to expand...

Oh ok. The other side? Not sure, I was only taking a photo of the bushings at the time. But if I'm going to replace one side, I might as well do both.

Is this what I need? (to fix both issues)

"Right and Left Heavy Duty Rear Tie Rod Assemblies"
"Right and Left Heavy Duty Rear Sway Bar Links"
$142.00

+ an alignment after, right?
 
LincolnLS_2013 said:
Oh ok. The other side? Not sure, I was only taking a photo of the bushings at the time. But if I'm going to replace one side, I might as well do both.

Is this what I need? (to fix both issues)

"Right and Left Heavy Duty Rear Tie Rod Assemblies"
"Right and Left Heavy Duty Rear Sway Bar Links"
$142.00

+ an alignment after, right?
Click to expand...

Yes, but I'd really rather have the OEM parts.
The real question here, is "is your rear anti-sway bar broken?" I can't see it at all in the picture, so I suspect that it is.
 
joegr said:
Yes, but I'd really rather have the OEM parts.
The real question here, is "is your rear anti-sway bar broken?" I can't see it at all in the picture, so I suspect that it is.
Click to expand...

Right, not just the links, but the sway bar itself... Will get my mechanic to take a look at tell me.

Is it even possible to get OEM parts 11 years later?
 
LincolnLS_2013 said:
Right, not just the links, but the sway bar itself... Will get my mechanic to take a look at tell me.

Is it even possible to get OEM parts 11 years later?
Click to expand...

Yes, those are still available. (Unfortunately, it is true that some other parts are no longer made, by anyone.)
BTW, that set looks like it may be missing the two bolts and nuts needed for the toe-links.
 
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