Find the engine oil fill, unscrew the cap, put oil in, check the level on the dipstick.
Depends on the engine in the Freightliner truck. Some require as little as 2 gallons, others require 11 gallons.
Motorcycle oil
4.8 quarts
As much as it takes. You could talking about anything from a Freightliner Sprinter up to a heavy haul truck.
That depends entirely on which engine you have.
It shouldn't.
Put Full Synthetic 10W30
Same oil you put in a car. Just make sure to use the correct weight.
6 qurts
4.5 quarts
Five
Yes