Manuals for GMC Engine Model Year Document 1 Series Maintenance Manual 305C V6 Overhaul Manual 305E V6 Overhaul Manual 351C V6 Overhaul Manual 351M V6 Overhaul Manual 4-71 Maintenance Manual 6-71 Maintenance Manual 637 V8 Overhaul Manual Duramax 2006 Manual Duramax 2003 Owner's Manual Duramax 3.0L Supplement Manual DURAMAX Diesel 2018 Owner's Manual Supplement DURAMAX Diesel 2016 Supplement Manual DURAMAX Diesel 2015 Owner's Manual G3500 Service Manual Gasoline V6 90 Degree 2001 Applications Manual Powertrain L35 2001 Applications Manual