A ha! It's the package tray...

[myk]

Well, it's in that area at least.  The very top part was replaced, but now when the car is idling in gear I get this INTENSE vibrating noise coming from the package tray area.  I noticed that if I physically push down on the package tray the noise stops.  Before I tear into my newly finished interior I just wanted some input: is this thing just loose?  Are there clips, screws or something that are supposed to hold it in place?  Is there padding or sound deadening supposed to be there?  If not, I guess I could sandwich some padding or sound deadener in-between the metal piece underneath and the softer material on top to kill the noise?  If the vibration and noise is because of the metal and softer top part not playing well together, how does a soft material like the top of the package tray make so much noise?  Finally, how do you go about removing the package tray if I need to get in there?  Thanks in advance, guys...

[doctor4766]

Well the back seat will have to come out. That means the rear arm rests and possibly crank handles will have to come out too.
I'd just put some padding in there and hope for the best, or turn up the tunes.....

[Just 6T9 CHGR]

The spot welds came loose on the rear seat cross brace on my car that would give me a rattle.....

[Back N Black]

Well, it's in that area at least.  The very top part was replaced, but now when the car is idling in gear I get this INTENSE vibrating noise coming from the package tray area.  I noticed that if I physically push down on the package tray the noise stops.  Before I tear into my newly finished interior I just wanted some input: is this thing just loose?  Are there clips, screws or something that are supposed to hold it in place?  Is there padding or sound deadening supposed to be there?  If not, I guess I could sandwich some padding or sound deadener in-between the metal piece underneath and the softer material on top to kill the noise?  If the vibration and noise is because of the metal and softer top part not playing well together, how does a soft material like the top of the package tray make so much noise?  Finally, how do you go about removing the package tray if I need to get in there?  Thanks in advance, guys...

I had the same problem and it took awhile for me to find it. What i did was crawl into the trunk and lift up the package tray enough to put small sticky pads( the kind you stick on the bottom of your chair legs) between the metal and package tray.  

[myk]

Wow, thanks for the replies, guys.  I just don't get how cardboard/particleboard/balsa or whatever that package tray is made out of can make so much noise bouncing against metal...

[bill440rt]

They do make a repro jute padding that goes between the package shelf & the particle board. Not sure if any of them had it originally or not. It was too thick for me to use in my '69, so I ended up covering it with sound deadener pads.
There are also supposed to be little angled retainer clips that hold the front edge of the package tray down. Your car might be missing those. I know I have an extra set somewhere...

[myk]

They do make a repro jute padding that goes between the package shelf & the particle board. Not sure if any of them had it originally or not. It was too thick for me to use in my '69, so I ended up covering it with sound deadener pads.
There are also supposed to be little angled retainer clips that hold the front edge of the package tray down. Your car might be missing those. I know I have an extra set somewhere...

I figured there would be clips or something holding it down, up or whatever.  When you say the padding was too think, do you mean to say that the package tray would be pushed up or distorted by the presence of the padding?  Just trying to get an idea of what I'll be dealing with here...

[tan top]

They do make a repro jute padding that goes between the package shelf & the particle board. Not sure if any of them had it originally or not. It was too thick for me to use in my '69, so I ended up covering it with sound deadener pads.
There are also supposed to be little angled retainer clips that hold the front edge of the package tray down. Your car might be missing those. I know I have an extra set somewhere...

I figured there would be clips or something holding it down, up or whatever.  When you say the padding was too think, do you mean to say that the package tray would be pushed up or distorted by the presence of the padding?  Just trying to get an idea of what I'll be dealing with here...

had a better picture of the clip thingys , but this is the only picture i can find right now !!
one each side !

[bill440rt]

They do make a repro jute padding that goes between the package shelf & the particle board. Not sure if any of them had it originally or not. It was too thick for me to use in my '69, so I ended up covering it with sound deadener pads.
There are also supposed to be little angled retainer clips that hold the front edge of the package tray down. Your car might be missing those. I know I have an extra set somewhere...

I figured there would be clips or something holding it down, up or whatever.  When you say the padding was too think, do you mean to say that the package tray would be pushed up or distorted by the presence of the padding?  Just trying to get an idea of what I'll be dealing with here...

Yes, the padding was too thick. The package tray would "bubble" up sort of speak, it was obvious when looking thru the back window. Didn't look right at all.

TT, thanks for posting that pic. Yep, those are the clips.

[myk]

Ok so I ordered the 'repro jute padding, but just to see if I could stop the vibration/noise in the meantime I randomly stuffed some extra weatherstripping in between the package tray top and the metal bottom and the noise is still there.  I have no idea where this noise could be coming from.  Does the entire pad need to be installed in order to buffer the tray and the sheetmetal from each other?  Here's another question: would a lack of interior rear window trim cause this vibration/noise also?  Also, why does this noise only manifest itself when my trunk lid is closed?

[charger Downunder]

Could the torsion bars on the trunk lid be vibrating

[myk]

Could the torsion bars on the trunk lid be vibrating

..........Hey that's not a bad idea-I'll look into that!  I figured with the trunk weatherstrip finally in place (what a mess that turned out be) and some rubber underneath the package tray any vibrations would be gone but noooooooooo....

[Ghoste]

Make sure the exhaust is hung perfectly.  I had a vibrating rattle in the back of my Charger much like the condition you describe.  Drove me insane trying to find it, I began to call it my "woodpecker".  I finally had a buddy drive the car while I was laying in the trunk and decided it was not coming from the interior.  It turned out to be a tailpipe just lightly touching a shock absorber under the right conditions.  Looking at it when the car was stopped, it didn't touch but you could see on the shock and pipe where they had been rubbed in the same area.  Loosened the clamp and turned the pipe slightly and my woodpecker was gone.
Not saying that is your problem but don't rule things like that out, I was absolutely CERTAIN my noise was coming from inside the car.  I had even torn out seats and interior panels hunting it down.

[myk]

Another good idea-I'll look into that, thank you...

[bill440rt]

Could the torsion bars on the trunk lid be vibrating

Might be on to something.
Look inside your trunk at the torsion bars, myk. There should be a rubber covering for sound/rattle purposes over one of the bars. It's basically a piece of hose (similar to rad overflow hose) with a slit in it to slide it over the bar, about 8"-9" long. Prevents the bars from rubbing metal-to-metal. If there's no hose, put one on there to see if it eliminates the rattle.

[stripedelete]

Take a ride in the trunk.

[Ghoste]

Take a ride in the trunk.

It worked for me. 

[myk]

Take a ride in the trunk.

It worked for me. 

Har-har!  Many summers ago, before I had the torsion bars set up properly I had to prop my trunk open with a stick.  I had gone into the trunk to do something or the other and knocked my prop rod out, and the trunk lid shut on me.  I was trapped in there for what seemed like a lifetime before my mom wandered into the garage and found me that way.  I'm never going into that space again unless I'm dead!  In any case, I DO NOT have any sort of hose-like material on the torsion bars.  I will look into that also!  Thank you all...

[Ghoste]

If you have someone trustworthy working with you then no fears.  If I were in your area you could trust me to let you back out. 

[myk]

Lol, oh man you guys are something else.  Well thanks to everyone here I think the problem is SOLVED!  I didn't have that piece of hose/plastic covering the torsion bars for the deck lid, so I grabbed some old hose, cut it in half and wrapped it around one of the bars; I had to wait for the car to warm up and get to the right idle-in-gear speed but it looks like the noise is GONE!  I tried taking the hose off just to see what would happen and the noise returned, so I'm pretty sure this is the answer.  Additionally, I think I see why I thought the package tray was the culprit: the torsion bars touch the bottom plenum of the package tray (when closed), which touches the bottom package tray, which in turn touches the top package tray which is why from inside the cabin it seemed like pushing down on the package tray was the answer.  I still have to drive the car and see if the noise is still there, but if it isn't happening in my driveway then it's probably gone.  

And, I can't help but think that in '66, or '67, or whenever Chrysler was testing their 2nd Gen Charger prototypes/test mules, they probably encountered this same noise in the field, crawled all over the car trying to find the problem and then came up with the idea for the plastic hose on the torsion bars.   Again, thanks so much guys-I'll post any updates if necessary...

[bill440rt]

 

[stripedelete]

Take a ride in the trunk.

It worked for me. 

Har-har!  Many summers ago, before I had the torsion bars set up properly I had to prop my trunk open with a stick.  I had gone into the trunk to do something or the other and knocked my prop rod out, and the trunk lid shut on me.  I was trapped in there for what seemed like a lifetime before my mom wandered into the garage and found me that way.  I'm never going into that space again unless I'm dead!  In any case, I DO NOT have any sort of hose-like material on the torsion bars.  I will look into that also!  Thank you all...

I understand the hesitation, but, back-in-the-day that SOP. 

[Ghoste]

Good to see that it's solved Myk.  I wonder how many rattles turn out to be things like coins down in the 1/4 panels?

[myk]

Good to see that it's solved Myk.  I wonder how many rattles turn out to be things like coins down in the 1/4 panels?

You know, it'd be worth spending the money and the effort to have the car torn down to its shell just to see what's lurking in all of the nooks and crannies.  As for my torsion rod vibration, I can still hear the faintest vibration but I can actually "play" with the tubing on the torsion rod, sliding it up and down to alter the pitch of the vibration.  You know, I might just cover the torsion rods end-to-end with rubber hose/tubing, as those things are smacked up right against the lower plenum of the package tray.  Are these things adjustable?  I noticed 3 different slots on the hinges themselves.  Also, I really need to stop working on my car in the pitch blackness of night, lol...

[Ghoste]

The slots are for adjustment.  Keep in mind, that changing the adjustment may mean the bars no longer hold the deck lid open.

[myk]

Great.  I'm going to get locked in there again...

[Ghoste]

Hmm, yes, you may need a trusted assistant.

[myk]

Good God I'm so ghetto: I placed rubber hose over both torsion bars, ha ha...

[HeavyFuel]

Here's what the orginal looked like for '68.

Pretty high-tech...

You might want to attach the little "s" connecter to hold the bars together.  That will help as well.  It lives under the hose.