Other people have posted similar issues with their dual disc's, You might check out the 'Towing and Hauling' forum way at the bottom of the main forums.
How are you starting? With these and most diesel trucks there is no need to 'stall up' the truck before you let out the clutch. I gently feather in the clutch from an idle without touching the throttle. The engine fuels up to maintain RPM. The only time I don't start this way is with a very heavy load or a intentionally hard launch.