2006 INTERNATIONAL Cab Chassis WORKSTAR 7300 - Serviceable worldwide?

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I'm looking at a 2006 International Cab Workstar 7300 4x4 for under $45K to be my expedition vehicle for a 18' cabin and I was wondering what kind of engine manufacturer they use and are these engines serviceable all over the world like the Mercedes/Fuso/Isuzu/MAN engines are? And the same question goes to the whole truck chassis itself including the Allison transmission? Finally, the fact that it doesn't have front/center/rear diff locks - is that a problem?

Here's the rig - https://www.commercialtrucktrader.com/listing/2006-INTERNATIONAL-WORKSTAR+7300-5033062074#sid=757803

What problems are I in for when traveling to South America, Africa, and/or Asia?