Peterbilt
Typically, 17k - 19k for a three axle freight truck.
Probably a bad vehicle speed sensor.
Two or more, depending on customer specifications, model, etc.
Yellow for the tractor brake control valve, red for the trailer supply valve.
102 inch maximum width without requiring an oversize permit.
102 inches
The weight of a 1990 Peterbilt tractor can vary based on the model and configuration, but on average, it typically weighs between 15,000 to 20,000 pounds (6,800 to 9,100 kg). Factors such as the engine type, cab design, and additional equipment can influence the exact weight. For specific models, it's best to refer to the manufacturer's specifications or the vehicle's documentation.
You should probably be a little more specific. Transformers is a long standing franchise, and the cartoon series alone has several 'generations'. Traditionally, in the cartoon series, Optimus Prime was a red Cab-Over-Engine tractor (he was shown as a Peterbilt 379 bonneted tractor in the movies).
Peterbilt makes Class 5 through Class 8 trucks, and the weight varies greatly between these models. Additionally, the application affects the weight - say, for example, you have a Peterbilt 330. Whether it's a single or tandem axle, what type of body it is, etc. will affect the tare weight. For a tractor unit (such as the 379, 389, 378, 359, etc.), you can expect a tare weight between 16,000 and 20,000, depending on the configuration.
The more high end tractors are the Kenworth W900L, Peterbilt 379EXHD, Volvo VNL64T770 and VNL64T880, the International 9900ix, and the International Lone Star.
Depends how wide the tires are set