One problem related to crankcase (pcv) has been reported for the 2003 International 4400. The most recently reported issues are listed below.
We've had two engine failures with this truck. The first occurred at 121,000 miles when an o-ring on a cylinder sleeve failed letting coolant fill the crankcase and requiring a complete engine overhaul that cost us over $6,000 dollars. The truck was more than 3 years old so we had to pay for the repairs. After putting only 40,000 miles on the rebuilt engine it has thrown a rod out the side of the block completely ruining the engine. It will have to be replaced at an estimated cost of $16,000. We have contacted navistar because the service technician said both failures were caused by poor workmanship, defective materials, or faulty design. Navistar has refused to stand behind their product.