I've spent all summer tracking down an annoying metallic rattle...starting to get irritated.

If information provided leads to the identification and eradication of my rattle nemesis, you become $50 richer.

Here are the details:

1) Rattle occurs consistently between 2600-3100 RPM. Usually it starts out around 2600RPM, and as the car warms up, the sweet spot moves towards 3100RPM.

2) Rattle occurs when the car is stationary, and when the car is moving...especially when under load.

3) Until tonight, I was pretty sure the rattle was coming from somewhere under the car...in the middle. Now I'm not so sure (see below). You can't really hear the rattle when under the hood, but that just may be because the engine noise is overpowering it.

4) 100% stock exhaust except for axle backs (Was GTAs now SSS Adrenaline).

5) Only other mod is a FRRP CAI (the older model made by Steeda) and Brenspeed 94 octane tune.


Steps taken so far:

1) Loosened and re-tightened midpipe and over-axle clamps many times, working with the midpipe preloads, etc. Rattle remains....

2) Removed GTAs and installed stock axlebacks. Rattle remains...

3) Installed SSS Adrenaline (which I ordered when I thought GTAs were the culprit...subsequently canceled the order, but they showed up at my door yesterday anyway...). Rattle remains...

4) Hypothesized that a particularly violent backfire damaged one of my cats. Purchased used stock H-pipe and cats for $100. Replaced mine. Rattle remains...

5) Verified all heat shields are solid. Rattle remains...


I'll gladly attempt to answer any questions you may have. Payment will be via Paypal.

 

How about the hangers from the tranny brace. After '07 they did away with these hangers because of known rattle. Apparently there was a TSB about it. Though I couldn't find it now. I think some bent the hanger part of the pipe out of the way and others just used a wheel griner to cut them off.

i have noticed under mine that the exhaust pipes pull down on the rubber grommets and actually touch the metal part of the bracket on the cross brace.

 

Hell, I'll add another 50 bucks. I get the same thing for the most part but a little higher in my rev range. Around 4000 or so.

 

It's not the coins in your cup holder is it?

 

Andrew if your car is a manual transmission I think I know what it is. The separator plate, between the rear face of the engine block and the transmission housing tends to vibrate and sometimes may contact the flywheel.

You need to go to the Dealership and have them remove the transmission and install a new updated separator plate.

This is the likely problem w/o me seeing your car, if its an automatic I'll try and think of what else.

 

Yep this is another possibility.
In fact try Gary's suggestion first. Its TSB 08-3-4

Is your car still under warranty, mileage? A dealer can do this for you.

 

could the K member be loose?

 

Mine has a similar problem, turned out to be the steel plate between the block and the bell housing did not have 2 bolts installed at the bottom. This allowed a small gap about .025" and the plate would vibrate coming into contact with the block. I think they are 10 X 1.25 mm bolts.

 

Thanks for the input guys. Both the hanger and separator plate theories sound plausible...I'll check them out tonight after work. I don't see anything wrong with just grinding off the hangers...especially considering I now own an extra H-Pipe

 

+1 on ManEHawke's seperator plate hypothesis. I had the same thing, it sounded like a very thin piece of sheetmetal was vibrating on the engine... because it was. I tried to show the dealer tech what it sounded like, but he couldn't hear it, even after leaving it at the dealership overnight for a cold soak test drive. Ended up they fixed it just by believing me that I heard it.

 

Fortunately my neighbour is the fixed operations (service) manager at a local ford dealership. I've just assumed all along that it was my GTAs causing the vibration, then my Cats (due to a rich tune/backfire?), so I haven't bothered him with it. I'll try the hanger thing first, otherwise I'll explain the problem and let him take it to work one day.

 

To me sounds like when one of my 02 sensors on my exhaust was loose.

 

Aaah, I had a large post typed up earlier, but the forum crapped out on my again as I clicked the post reply button. Here's the short of it:
Wrap the tips of your exhaust hangers in electrical tape (the part welded on to the muffler). Upon visual inspection I couldn't see how they would be rubbing and causing that noise, but after wrapping the ends of the hangers in several thick layers of electrical tape the noise went away and I was able to ID and correct theb problem. Give it a shot, it'll take 3 minutes to try.

 

John that's a great idea and I love the avatar

 

it's that TSB thing for the flange that I had to have replace and then it was all better ! I can dig up the paper work & sent you its description or post it here & I don't need any reward toward another Mustang Fan !

 

A) Try removing the two bottom bellhousing bolts and insert some doubleside foam tape between the plate and housing lip. Re-install the bolts. I have seen threads where the owners did this and it worked.
http://www.stangnet.com/mustang-foru...ing-sound.html

B) Another vibration post said the service rep told him that the rattle did not pretain to the TSB, but they did find the possible source. They found the brake cable had more stack than usual and that it was possibly hitting the exhaust or the underside of the floorboard. The cable was tightened up and an insulating pad was installed on the floorboard. The poster said he has not heard it since.

Good luck!

 

I have chased down several rattles in my car, and the most annoying one was the transmission crossmember mounted exhaust hangers. I used a pipe wrench and twisted them right off the car. Rattle gone.

the rear hangers will rattle also and sometimes you can just tweak the hangers with a pipe wrench.

another source was my adjustable panhard bar, make sure if you have one that it is tight and not bent or tweaked at all.

the little lockers on the rear suspension nuts (I believe these are referrred to as J-bolts) also rattle and need to be DESTROYED. I hate them.... locktite works better.

Took me almost a year to track down the crossmember rattle though...so nice once i found it.

good luck!

 

I've got the same thing, started about a month ago. Hits me about 2700 RPM under load.

I was going to take the car in next week for service, have that looked at, and another bad sound from the dash (blower fan or something knocking 8-10 times on startup, every time).

Unfortunately my 3/36 warantee is up, but the drive-train 5/50 is still good.

We'll see how much this'll cost me.

 

ManEHawke...I owe you 50 bucks! PM me your PayPal info.

Was going to check out the H-Pipe hangers first...but while I was down there I noticed a mm or so of clearance between the separator plate and the bell-housing. Slapped on a pair of vice grips....rattle GONE!

I'm going to try out Cdynaco's suggestion of some double-sided tape first...I'm pretty sure that'll do it. Otherwise, I had my service manager neighbour under the car a few minutes ago, and he said he'd take care of it no problem.

Thanks for all the input...

 

Sweet!

I'm glad you were able to find it so quick. TMS rules.