How much does an 2000 international tow truck weights?

Anywhere from 15,000 to around 50,000 depending on what it is. The chassis (remember that Navistar makes trucks from Class 5 medium duty trucks up to Class 8 heavy duty trucks), the aftermarket recovery apparatus (cranes, wheel lifts, etc), and the drivetrain all factor into this, and you didn't specify a model or class of truck, nor a class of wrecker for us to go off of.