7 qts
8qts
It depends on the tractor.
what is the oil capacity for the ford 3415 tractor
As much as the fuel tank can hold
Depends...by "diesel tractor" do you mean "farm tractor" or "semi tractor"? You're SUPPOSED only to put off road diesel in a farm tractor. That's why they make it. If you have put it in a semi tractor, get hold of your dispatch/brief/lawyer right away for advice on what to do. If you have a pre-2007 engine your trouble is almost exclusively legal. If your engine is 2007 or 2010 compliant, you're probably going to screw up your EGR and diesel particulate filter, which will break your engine.
15 quarts
three quarts
None. They use diesel fuel, which a North American tractor might hold up to 300 US gallons of (although 250, give or take, is a bit more common).
about 15qts
68 litres
15 gallons or approx 56 liters
the mk5 mk6 mk7 diesel van standard fuel tank is 60 ltrs