CHART lNFORll lATlClN PAGES CHART DEE lGN The charts are designed to list all items which are details of the Major Assemblies listed numerically at the top of the chart pages l lajor 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 WheelsrFri nt Drurn Hlub Vi heel 5 307 The text group lists l lajor Assemblies with applicable description model and year usage Service notes are provided to guide proper location ot service parts Parts used in conjunction with l lajor Assernblies and are not listed as details are located in the appropriate text group l lang on or loose items TO LOCATE F AR I 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 Major Assembly jziarts book group l lajor Assembly details are listedalphabetically in a vertical chart form by line number Each line has one description only and includes GMT and WDDGM group numbers for reference General l lotors uses two different grouping systemis for truck parts books The GMT system is used for all heavy duty model parts books and the WDDGl l system for the medium duty model books Please reter to the General Information Pages for detailed parts group usage information IF NOUN NAME IS NCllT Kl lOlWN Refer to the illustration C3ataIog keeping in mind the li lajor Group number and described area Locate the appropnate illustration and cletermiine the part required on the illustration The noun name and grouo number is listed inthe legend Please refer to the Illustration Catalog Introduction pages for additional user inlormation IF NOUN NAME IS KNIOWINI Refer to the Alphabetical Ilndex as a guide to identity 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 andror usage is also provided to assist identification Locate the l lajor Assembly part number at the top ol the chart and scan down to line numlber of the parts noun name ln this box you will find the quantity required part number and vendor number or note 4 1 CHART