I read this not too long ago in a automotive magazine. The new HD 3500 trucks are supposed to have a rear axle with an 11.5" ring gear..last year was the 10.5" 14 bolt. They will use the old 14 bolt in the 2500..except with the diesel..and with it they will use that new 11.5" rear end. If i remember right.
Also I read that GM will stick with the independant front suspension, instead of a solid front axle...however, front control arms will be constructed of cast iron instead of stamped steel.
Here are some quotes from this months Car and Driver:
"Here comes mey next assignment, a GMC 3500 Diesel Dually with a 5th whell tow hitch in the bed, hauling a 30ft enclosed trailer balasted to the gills." "The rig weighs a max gross total of 22,000 lbs..the highest combined GVWR of any pickup..anywhere. The big diesel hustles to 55mph uphill--with, if not alacrity, at least fearsome inevitability." "I'm hooked, both literally and figuratively."
"It's a 300hp 6.6 L V* diesel with 520 ft lb of torque-that's 63 more than a Lamborghini Diablo twists out-and it rumbles like a polite Corvette. No smoke, no tack tack tack idle, no ball-peen hammers when you accelerate hard, excellent throttle response, and (we're told) easy starting in subzero weather."
Tim