400 mack

Hello my name is Greg. I am new to the forums and to mack trucks, I bought a used 2001 mack triaxle dump, it has 301,000 miles and oil looks clean, and it has no leaks. But the blow by tube is slobbering. So i assume theres antifreeze in oil, is there a way to tell if its a blown headgasket or sleeve? I know how to pull pan and valve covers to pressure test, how do you tell if its a sleeve or head gasket? any help appreciated thanks