Rob Gronovius was right; free downloads of manuals & photos and much more via U.S. Army Heritage & Education Center (U.S. Army Military History Institute).
Jon; that information you wanted on M60 AVLB, and the M728 is here for free.
There is so much information stuff might be difficult to find but I downloaded the manual for the M24 tank after just a minute or two at the site. With DSL the download took a couple of minutes, in pfd format. With the right search you can also find alot of printed reference books and personal accounts. Includes photos and paid research if you wanted to go into that much detail.