you said it may be boost related so it might be the ARV.
The best way to check this is to have someone (you trust

) put it in drive and apply the brakes and accelerator while you search for the squeal under the hood.
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green 85 300SD 200K miles "Das Schlepper Frog" With a OM603 TBO360 turbo ( To be intercooled someday

)(

Kalifornistani emissons

)
white 79 300SD 200K'ish miles "Farfegnugen" (RIP - cracked crank)
desert storm primer 63 T-bird "The Undead" (long term hibernation)
http://ecomodder.com/forum/fe-graphs/sig692a.png