Machine description: Cat 6 Cylinder Diesel Engine, 6-Speed Manual Transmission, 10000 lb Front Axle, 21000 lb Rears, 31000 lb GVWR, 11R22.5, Spring Suspension, 242 in Wheelbase, 22 ft x 102 in Wide x 89 in High Body, Walk... more info about the 1998 GMC 7500.