Here's some ebay offerings. The operation and maintenance manual is the one you want, the parts book may be ok depending on your serial number range (I'm assuming it's a 47A series as you say it's manual clutch).
http://www.ebay.com.au/itm/CAT-Caterpillar-D7-D7E-OPERATION-MAINTENANCE-MANUAL-TRACTOR-OPERATOR-47A-79A-DD-/370870436054?pt=BI_Heavy_Equipment_Parts&hash=item565999c0d6
http://www.ebay.com.au/itm/CAT-Caterpillar-D7-D7E-PARTS-MANUAL-BOOK-CATALOG-TRACTOR-BULLDOZER-47A3396-5841-/370633926022?pt=BI_Heavy_Equipment_Parts&hash=item564b80e586
Very important that you check oil in the pony engine and keep it clean. Also I have noticed many novice operators try and rush the starting procedure. The design of the pony engine routes the pony engines exhaust through a passage in the main engine intake manifold which warms the intake manifold and makes starting the main engine easier. Allow the pony engine to fully warm up before attempting to engage the pinion with the main engine and you will greatly increase the longivity of the pony engine.
Keep the coolant up and radiator fins clean, don't overheat the engine, don't want cracked heads.