Rattle/Grinding Noise when stopped, in gear

[NJshadow93]

I just bought my '06 SR5 V8 a little over a week ago, and drove a lot, putting over 400 miles on it since purchase. I just hit 110,000 miles as I pulled onto my street last night. When I was going back out, I put it in reverse and heard this strange rattling/grinding noise from the rear end. I kept it in reverse, with the parking brake applied and stepped out to try and hear it, but could not hear it; at least not as loud as I did from the inside. When I put it in park, the noise stopped. It started again when I put it into drive. I rolled down the street where I still heard the noise so I turned around and borrowed my dad's car.

Any idea what it could be?

I was thinking possibly a loose skid plate or heat shield? I didn't notice the noise all day and just heard it for the first time last night after driving over 100 miles yesterday. Could it be a rear differential problem? I don't think it made the noise when I accelerated, which led me to believe something is loose down there.

I had my Gibson exhaust put in 5 days prior and everything seemed normal so I didn't think there's any connection. Thanks for any help.

 

[Atlanta_man]

In gear
parking brake applied
driver out of the car

RUN for your life

 

[DC runner]

Sounds like exhaust. Diff's don't rattle, they grind or whirr. The bearings going.

Exhaust rattles as the resonant frequency impacts it. My guess, your new exhaust is not well insulated as the original was. Happens.

I wouldn't worry about it.

 

[NJshadow93]

I just went outside, and could not replicate the noise. Very strange. I got under there and the heat shields look fine, and I pushed them and they didn't move. I had the same exhaust on my '03 and had it pulled when it was totaled. It had to be cut a little bit to fit the VVT-I V8 (which I think has an extra cat down there?) but like I said, last night was the first I heard the noise. I was surprised I could not replicate the noise today. I put it back in park after trying reverse and drive and I heard it SLIGHTLY. I revved the engine a bit and nothing. Thanks for the reply. Other opinions are welcome

 

[ChaosStarter]

I agree with DC Runner, definately seems like a loose heat shield or something of that nature. You won't hear differential noises at a full stop. Sometimes those heat shields will hit that perfect resonance frequency and only happen at certain times.

 

[CXS]

I have that noise too, happens now and then and can't be replicated on demand making it very hard to locate. I'm 90% certain it's the already mentioned heat shield vibration. I plan to add fender washers to the fasteners which I've heard works to stop the noise.

 

[Doozi]

I would agree with the resonant frequency diagnosis. I drive a '98 Ford Escort as a commuter... you should hear that thing! I can just about make it sing by changing between R, N, D, and switching the AC on and off. Heck, even turning the headlights on and off at idle creates different vibrations.

In your case, it could be something along the exhaust system (coupling, hanger, shielding, etc.) or the insides of the muffler. And you won't always be able to find something loose as the culprit. In a lab setting, I've seen (with a stroboscope) parts of an assembly fully torqued and solidly mounted, vibrate like crazy and resonate sound at certain points during frequency sweeps on a vibration table.

 

[CXS]

The noise is pretty much limited to idle speed. As the OP stated it's when stopped as is mine.

 

[NJshadow93]

It is definitely something rattling around down there. My guess is that something is loose because I never heard it before last night. I just took it for a ride and I can hear it on every little bump in the road. I'm not very car savvy but anything you can recommend I check down there before I have a professional take a look? I am taking it in on Tuesday for the timing belt service will probably have them look at it if I can't figure it out myself.

 

[ChaosStarter]

It is definitely something rattling around down there. My guess is that something is loose because I never heard it before last night. I just took it for a ride and I can hear it on every little bump in the road. I'm not very car savvy but anything you can recommend I check down there before I have a professional take a look? I am taking it in on Tuesday for the timing belt service will probably have them look at it if I can't figure it out myself.

Depending on where you live in NJ, I could always check it out at my Toyota dealer in central NJ. How much are they getting you for the timing belt?

 

[CXS]

That's very different then. In your 1st post you mentioned it happening when stopped, if it's happening all the time It is most likely connected to the new exhaust if it's happening 5 days after installation. The expansion/contraction along with normal movement probably loosened something. Have the installer give it a once-over. I think you'll find all's well after that.

 

[NJshadow93]

Depending on where you live in NJ, I could always check it out at my Toyota dealer in central NJ. How much are they getting you for the timing belt?

I'm getting a great deal actually, $899 for everything, timing belt, water pump, serpentine belt, tensioner and pulleys.

EDIT: I'm in Northwest/Central NJ in Hackettstown

 

[NJshadow93]

That's very different then. In your 1st post you mentioned it happening when stopped, if it's happening all the time It is most likely connected to the new exhaust if it's happening 5 days after installation. The expansion/contraction along with normal movement probably loosened something. Have the installer give it a once-over. I think you'll find all's well after that.

Yeah, I just noticed it happening while driving. Basically because last night when I heard it while stopped, I didn't drive it.

 

[ChaosStarter]

I'm getting a great deal actually, $899 for everything, timing belt, water pump, serpentine belt, tensioner and pulleys.

EDIT: I'm in Northwest/Central NJ in Hackettstown

That is pretty good actually. You might as well throw in the radiator hoses as well since they have to come off anyway. Might only add another $100 for the hoses/clamps. They sohuldn't charge you any extra labor on them, since like I had mentioned, they have to come off anyway.

 

[NJshadow93]

Should I be worried about driving it for the next few days before I can bring it to the shop that put the exhaust on? Probably wouldn't be able to bring it until Thursday.

 

[NJshadow93]

Just thought I should give an update. I got under there that day and tapped the exhaust with my hand. It rattled slightly, just enough to hit the frame. I took it back to the shop and they had to tighten and bend some brackets. The exhaust is nice and tight and sits perfectly now.

 

[4everOK]

This issue just occured for me and after i googled it this thread correctly diagnosed the problem - exhaust heat shield was the culprit.

 

[Racetruck_V8Runner]

I had this problem when I got my exhaust done. the heat-shield was hanging down on one side rattling against the exhaust pipe. I just yanked it off since I have a glasspack and there is more space between it and the car than there was when I had a big muffler there almost touching the car bottom.