There are several interchangeable models that will replace that 60 amp alternator (NSN 2920-00-909-2483 off the top of my head). Quite frankly, they can often be repaired by replacing the voltage regulator, which is the whole rear plate on most of them. But before that, try and adjust the voltage. You have to remove a small allen key plug, and with a small screwdriver you turn a little potentiometer until you get a charge of around 28 volts.
The MLVW has an interchangeable alternator. You could check with prefair surplus and see if they still have any. The same alternator was also used on the 5 ton diesel, the M151A2, and the 5/4 ton in case you have access to any of those for parts.
They are also on ebay all the time. A search for that NSN shows them starting at $375 or best offer.
http://www.ebay.com/itm/Prestolite-A...f81e13&vxp=mtr