LeeSoCal Posted November 5, 2005 Share Posted November 5, 2005 Looking for a low 5s differential gear ratio for my 49 Mack EH. The diff I have now is too slow for these California freeways and I am getting in the way. I have checked with Watts Mack and they have nothing and computer cannot locate anything in any of their dealers. Would love to find a new ring gear and pinion but would also accept a whole punkin. My parts books show a 5.125 ratio that is also available for this truck. The part number is 4 QFA 539A-P5. My book shows this is a 1500 series diff. I don't know what that means. The serial number for this diff is CR25 883 79. It is a single reduction and has air brakes. Quote Link to comment Share on other sites More sharing options...
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