CHART INFORMATION P AGiES CHAFIIT DlESIGNl 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 header which identifies the major assemblies listed and the text group they are found in example Wheels Front Drunn l lub Wheel 5 307 The text group lists Major 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 lajor Assemblies and are not listed as details are located in the appropriate text group l lahg on or loose itemsl TO LOCATE PAR I lE5 Major Assemblies must be k nown Please refer to major assembly identification aids vehicle serial number plate triuok broadcast sheet service parts identification label major component part number label Major Assembly parts book group Major Assembly details are listed alphabetically in a vertical chart form by line number Each line has one descriptioni oinlly and includes GMT and WDDGM group numbers for reference General Motors uses two ditterent grouping systems for truck parts books The GMT system is used for all heavy duty model parts books and the llZZlDGM system for the medium duty model books Please refer to the General information Pages for detailed parts group usage iintormation IF NOUN NAME IS NOT KINIOIVIIN Refer to the lllustration t3ataIog keeping in mind the li lajor Group number and described area Locate the appropriate illlustration and determine the part required on the illustration The noun name and group lnurinber is listed in the legerld Please refer to the Il ustration Catalog ntroduction pages for additional user information IF NOUN NAME IS KNOWN Refer to the AIphabetical 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 rising group number as a guide Description and or usage is also provided to assist identitication Locate the Major Assembly part number at the top ol the chart and scan down to line number of the parts noun name In this box you will find the quantity required part number and vendor number or note sm ciiriitr