6.9 Diesel sound deadening package

[Rockhauler]

Sent some pictures to Gary and found out the diesel trucks came with a sound deadening package, was this optional or standard equipment on the diesel trucks?

In the engine bay the hood underside has a blanket attached, both front fenders have it applied and it also flows in one piece down over most of the plastic inner fenders, and there’s another blanket from the heater box across the firewall to the drivers fender.

On the interior there sound deadening material behind the kick panels. On my truck there was 2 pieces of plastic with about 1/2" of foam glued on that was attached to the underside of the dash back towards the firewall. This is different material so wondering if this was from Ford or a previous owner mode.



 

[ArdWrknTrk]

I'm no IDI expert but every diesel Bullnose I've seen has this insulation on the firewall and in the kicks.

Maybe someone like Mryl who worked in the dealership back then could give you a definitive answer?

[Gary Lewis]

I think what we are looking at is option 912 EXTERIOR SOUND PACKAGE.  The 1984 Light Truck Data Book says "Use with 6.9 liter (420 CID) engine or F-350 series over 10,000# GVWR"  As for cost, in that application the wholesale & suggested retail were "N/C".  But "Use with all other applications" the wholesale was $10.72 and the retail was $12.70.

My guess is that the diesel trucks came standard with that, but I haven't been able to prove it - yet.

[Gary Lewis]

Let's see if this page from the 1985 Truck Facts Book helps.  Apparently when you ticked the box to get the optional diesel you got a reduced exterior sound package and a Sound Insulation Package.  I can't find a listing for either of those packages so we don't know which of those two contributed what items on your truck.

[ArdWrknTrk]

As always, you have the documentation.

You're invaluable, Gary!  👍

[Ford F834]

From years of junkyarding and pulling parts from IDI’s I have always seen the engine bay sound deadening stuff, or remnants of it. Hood, firewall, fender aprons and inside of the fenders. The interior sound deadening items are more hit and miss… notably the molded foam blanket on the inside of the firewall below the dash. My 86 crew cab has that, but does not seem to have the jute lining on the kick panels or under-dash plastic inserts with foam. Or perhaps they are just missing. Your sound deadening package is remarkably preserved! The pieces I am used to seeing are typically tattered and gross.

One unusual item that I have seen only once on a early first year 1983 IDI (manufactured late 82) is a pair of heavy, thick, foam rubber fender profile cut-outs that were clipped to the cab seam at the firewall. Of course, this would be extremely easy to overlook unless you were looking for it specifically. They were not present on my 86 CC.





Of course with the IDI a large portion of the noise comes from the intake, so adding a turbo helps 😈. There is speculation that this was part of the purpose of the “soup bowl” on the 6.9 air cleaners…

[Rockhauler]

Thanks for the info guys up here the only other 6.9 I've seen is in a scrapped school bus.