1972 ford f - 350 , 5000 gallon water truck, weight
If the vehicle has an automatic transmission, it will have a dipstick. Manual transmissions do not have a dipstick.
If that is an automatic transmission, pull the dipstick and read it, it will tell what fluid to use.
Because you cannot haul very much in a car. It was invented to haul cargo not passengers.
Because you can pick up things.