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"Tim Louquet"
wrote:

The truck has a "sound deadening package" installed from the factory which
essentially insulates the engine compartment, but it does not insulate the
doors/interior. I will most likely try to Dynamat the doors to help with
the noise issues.

--
Tim

There's not much gold to be mined there. In 1993 I tested a 2-step Dynamat
installation on my new Z-28.

The 1st step, all work was done by a Dynamat recommended car restoration
service, included a layer in the doors and a layer on the floor from the
firewall tothe rear hatch area.

The 2nd "Pro-Install" step put a 2nd layer on the areas included in the first
step and also a layer on the entire hatch area. Total cost to Car Stereo Review
was $1600.

I made three complete sets of measurements (before and after each step) at
idle, and 35-mph and 55-mph on smooth and rain-grooved pavement on the same
stretches of road, same days of the week at the same time of day. Each set
included an average of 5 runs eachand covered the full spectrum (not just a
single SPL reading) with a MLSSA acoustic analyzer.

The resultant noise reduction? Nada except for a slight reduction in tire whine
in rain-grooved pavement.

Why? There's just not enough mass to significantly attenuate noise. The obvious
stuff like open holes and the like have been attended to at the factory. If
you're luck you might find through sound leaks in your doors. But you just need
to seal those, you don't need Dynamat for that.

Window/door weather/wind seals are usually a better place to look. Also make
sure your vehicle has a hood liner but it sounds like it already does.