David, lets break down the manuals to their major purposes
-10 is basically the operators manual. This should do this, for this reason, etc.
-12 is a lubrication order
-24 is the troubleshooting manual, and where the majority of your time should be sent absorbing.
-24P has all the exploded parts diagrams, and reference numbers (which can then be parlayed into sourcing of parts using the internet)
https://www.steelsoldiers.com/showthread.php?175591-MEP-803A-All-the-TM-s-you-need has all that are referenced above, plus some others (injector testing, trailer mount sets, etc).
When most jargon is thrown around, it is from -24 (IMO). There are also -24 and -24P for the engine only (also in that folder).