CHART INFORMATION F 1llGES CHART DESILIGNI The charts are designed to list all items which are details of the Major Assemblies listed numerically at the top of the chart pages Major Groups may contain more than one chart Please note each chart has a description lheader which identifies the major assemblies listed and the text group they are found in example Wheels Front Drunn Hub Wheel 5 307 The text group lists Ma jor AssernbIies with applicable description model and year usage Service notes are provided to guide proper location of service parts Parts used in conjunction with l Iajor Assemblies ancl are not listed as details are located in the appropriate texi sgroup I lang on or loose items TO LOCATE Fl AR T1S Major Assemblies must be known Please refer to major assembly identification aids vehicle serial number plate truck broadcast sheet service parts identification label major component part number label IVIajor Assembly parts book group Major Assembly details are listed alphalbetically in a vertical chart form by line number Each Illne has one description only and includes GM ll and WDDGM group numbers for reference General Motors uses two different grouping systems for truck parts books The GMT system is used for all heavy duty model parts books and the WDDGM system for the medium duty model books Please refer to the GeneraI Informaticiln Pages for detailed parts group usage information IF NOUN NAME IS NOT KNOWN Refer to the Illustration Catalog keeping in mind the Major Group number and described area Locate the appropriate illustration and determine the part required on the illustration The noun name and group number is listed in the Iegend Please refer to the llIustration Catalog Introduction pages for additional user information IF NOIJN NAME IS KNOWN Flefer to the AlphabeticaI Index as a guide to identify group number Please note lf the group number is not found in the text the group is charted Scan down the chart lines and locate noun name using group number as a guide Description and or usage ls also provided to assist itilentification Locate the Major Assembly part number at the top ef the chart and scan down to line number of the parts noun name lin this box you will findl the quantity required part number and vendor number or note 5 68A CHART