Re: [Amc-list] droning sound

[Tom Jennings <tomj@xxxxxxx>]

On Sun, 25 Feb 2007, d stohler wrote:

>  the thing with these
> cars, unlike cars with subframes or frames, there are
> no bushings between the frame and body. the suspension
> mounts are the only bushings. they mount strait to the
> chassis. the body pannels come strait off of there. it
> can cause an amplifying effect in certain cases. i
> think that is what we are expirencing.


I dunno about that... in fact the driveline itself is BETTER
insulated in those 60's full-sized torque-tube cars than in
later open-driveline cars.

My 63 Rambler has a lot of wind noise, but the driveline is
UTTERLY SILENT, as quiet as our 96 Honda, or less. Absolutely
vibration free.  No buzz, drone, etc. Zero. It's the classic
"can't hear it run" car. 324,000 miles, I maintain it well but
it's no show queen and I improvise a lot of parts.


One overlooked part are the rubber thrust bushings that isolate
the transmission crossmember. I made new ones myself out of
cheap red poly bushings. When they collapse (from old age)
you get horrible intermittent noises on decel or accell.

There are (or were :-) rubber pads on top and bottom of the
rear springs. They probably collapsed; I use 1/4" 60-durometer
neoprene pads cut to fit (that sh*t's pricey! $25 for a 12x24"
chunk).

The panhard rod bushings also make a noise difference, mine
are garbage, I'll replace them "some day"... :-)

None of these are likely to cause a continuous predicablt drone,
but they will amplify noises already present.

Don't underestimate those trans thrust bushings! For such an
important part no one's ever heard of them!


> i put some of
> that sound deadening insulation in the trunk area, and
> back seat area. that helped DRAMATICLY.

My guess is you have bad tires, bent wheels, lateral tire
imbalance, etc.

Unless they are BROKEN, or assembled wrong or with wrong parts,
torque tube rears are very quiet, and since they're sealed,
they tend to last forever. They are a major PITA to work on
when you have to ! as I'm sure you know.


Unit-body cars are very rattle-free in general. My crappy old
Rambler has no noises that I don't know exactly what they
are: rear tool hatch cover, pass. door innards, poly strut
bushings, ... Short of a bad crash repair or terrible rot,
there's no chance of an internal panel buzzing against the
frame or whatever since it's all welded into one blob of steel.

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