Think'n of Buy'n a Big Pusher - ?? Check it out How ??

A big bus? Ah come on. The owner is going to change oil. An Allison with problems will have its fluid changed probably twice trying to cure the problem.

Note: Big diesels can develop coolant leaks. One is called a "cold leak" when parked. The 2nd is a "hot leak". Pressure testing the cooling system can reveal a lot of problems including heads gaskets leaks. A cylinder Leakdown Test reveals compression issues.