A couple applicable manuals I found the numbers online for this trailer would be:
TM 9-8242, Operation Organizational Maintenance, and Ordnance Field And Depot Maintenance 10-Ton 4-Wheel Flat Bed Trailer M345, 1957
and
TM 9-2330-241-14&P, OPERATOR`S, ORGANIZATIONAL, DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL (INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST) FOR TRAILER, FLATBED, 10-TON, 4-WHEEL, M345 (NSN 2330-00-200-1737), 1985