1/4 to 1/8th of a gallon, all factors dependent.
The current API rating for diesel engine oil is CJ.
Diesel #2. During the winter in the states that get regular temperatures in teens and below, you should use diesel #1 because diesel #2 will gell at lower temperatures.
Between four and nine, dependent on a number of factors.
1,000.000.
Depends on which engine it has.
300 to 650hp
The norm will be between 22 and 25 tons.
In the range 2,000 to 2,500
22 to 25 tons, typically.
Not a drop. 18 wheelers don't use gas - they use diesel. As for how much fuel they carry, it depends on how the owner orders it. For a daycab which is only going to run short distances, there really isn't any need to hold 300 gallons of fuel, and it might only hold 100 or 120 gallons. For a line haul truck which travels long distances, 200 - 300 gallons is typical, with 200 - 260 being the norm.
18 wheeler has the higher gross weight