Can any one tell me if there is a way to tell if I have a heavy duty or a light duty truck? The truck is a 1986 3/4 ton 4x4, dana 44 up front and 14" GM rear. It also has 8 lug 16.5" rims. Im not sure but I have heard there is light and heavy duty trucks in 1986 Dont know if source is dependable. Thanks for the help!