I have a 2011GMC Sierra 4WD 2500HD crew cab standard box with a diesel engine. I wish to increase the towing weight of the vehicle to a 3500HD model. To do this in australia I beleive that I have to change the tyres and rims. Add extra springs and change the torsion bar. If I do all of that I can get an engineer to certify it at the new towing weights as per 3500 model. But I also have to provide evidence that the brakes, drivetrain, axles, diff are the same as the 3500.
To get this information in Australia is very difficult as they are not common vehicles. So what I need is proof that the above areas are the same..i.e. detailed manufacturers specifications, orcopies of relavent pages from repair manuals from both models also perhaps an engineers statement or mechanics statement stating the difference between the two models in relation to suspension, brakes etc.,
Then I can do the changes hand over the paperwork to the Australian engineer and he can certify it.