I've searched the forum with no luck. With the weather really warming up, I'm driving with the windows down. My question is this...

Whenever I drive over a bump, I can hear a sound from underneath the car, like a bag of chains being rattled once or twice? It literally sounds like a bag that has a length of heavy guage chain link being dropped/rattled once or twice, at the same time my rear tires roll over a bump? It sounds as it it's coming from more of the REAR of the vehicle, because I notice this clanging sound when my rear tires roll over a bump, not the front tires.

I have an 05, 44k miles, w/the sport package+18" rims (no loose hubcaps..lol). All lugs are tight. I was thinking maybe something in the rims or brakes, but if I roll over a bump with the brakes on, I still hear this unusual noise from underneath the rear primarilly when the rear tires roll over the bump? I'm tempted to say it's more prevalent from the drivers side, but that may not be true. It's just my ear is hanging out the window on that side.

I have not put the car up in the air yet or crawled underneath her to take a peek yet.

Any suggestions?

 

Let me add a little more. I am not carrying/transporting ANYTHING in the car, aside from the title, owners manuals, etc. Also, the fullsize rim is very securely in place, along with the jack kit properly stowed. There is nothing loose on the interior of my car, basically.

 

Did you change your brakes lately. I had a problem like that when i changed my brakes. It was the pin that slides inside the bracket that holds the brakes in place. If the pin is not properly inserted into the bracket properly it will rattle over every bump. Mines was the rear passesnger side, maybe it just broke or worked its way loose somehow.
Hope it helps you out.

 

WOW. If it's what you're saying, I owe you! As I just bought the LS (from a private seller) about a month ago, I don't know when the brakes were last replaced. The seller DID say they were "recently done" though.

I DID have it "inspected" (from the local Lexus dealer) top to bottom before I committed to buy it (cost $210), and Lexus's report stated the measured pad thickness on the front pads had 9mm left on them, and the rear 8mm left on them. I'm betting the bracket/pin you mentioned is the problem. How thick are pads brand new--like 11-12 mm?

I will advise this weekend when I have several undisturbed hours with her! Thank you very much again!

 

Any update on the noise? I have the same deal going on.

 

I had my front brakes done a month ago, and this exact problem/sound came up right after the brake job. I only hear it on rougher surfaces coming from the front right wheel area. It is loudest when driving down a narrow road with trees or barriers for the sound to echo off of. I removed the front left tire over the weekend and found nothing loose, but it may warrant a closer inspection when I do the rear brakes this weekend.

 

I had basically the exact same thing on my '00 GS300 Platnium I had before my '01 LS430 UL. It is most likely the heat shield on the catalytic converter. The clamp and screw was rusted and old which made it loose. I got a new clamp and replaced it. Be fore that I just pinched the slack of clamp with a pair of pliers until I got the new clamp. It's really easy to do. This is a common thing to happen on any car in general. It doesn't always happen, but sometimes it does. So I definitely recommend checking that out.

 

I have to agree with several others here, check the brakes first. The pad backs, shims, and retaining pin all need a nice coating of grease or it can tend to sound like a bag of tin cans when you go over a speed bump. One other thing to check is your exhaust where it goes over a crossmember in between the rear catalytic converter and the center resonator assembly. Make sure it has plenty of clearance over the crossmember. If not, you have to loosen the exhaust clamp at the front of the resonator assembly, raise the exhaust, then re-tighten the clamp. Also helps to wrap a metal hose clamp around the rubber exhaust hangers to prevent them from stretching out too far and letting the exhaust hang too low. Easy fix, just place the clamp around the hanger like a band clamp and tigthen it down enough so that the exhaust doesn't move so much.

 

I had the same problem on mu 07 LS460L. Found small stones had accumulated on top of the sound insulating panels underneath the rear of the car. Hard pounding of those panels released almost all of the stones, some remain requiring those panels to be removed, emptied then replaced. I still have the same noises from the front - probably due to those panels also collecting stones.

I also have a physical oscillation through the car following bumps due to manhole covers etc. This oscillation lasts only a fraction of a second and tails away quickly. Local Toyota dealership changed a mounting clamp on the exhaust, no change.

The "hesitation on acceleration" is a bug which always appears following a dealership service. Goes away after a few miles then comes back maybe twice a year afterwards.

I also have a 20 year old Audi A6, still my preferred drive.