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Front differential replacement / gear ratio?

Discussion in 'Chevy Trucks' started by coreyod21, Dec 28, 2012.

  1. coreyod21

    coreyod21 Member
    Messages: 44

    On my first time out plowing ever I broke my front differential bracket which led my steering to lock up and my front u joint to smash my oil filter spilling oil everywhere. Anyways Im looking to remove one from a junk yard tomorrow but I wanted to know how can I tell which gear ratio is needed for my truck. I have a 1997 silverado k1500 with the 5.7 vortec motor. It seems fairly easy to remove and swap out but im concerned on getting the wrong gearing ratio. I believe I can tell the ratio by the the numbers in the glove box but I dont know what to look for. Any help please?
  2. Mark13

    Mark13 PlowSite Fanatic
    Messages: 5,794

    GU6=3.42 GT4=3.73 and GT5=4.10.
  3. theholycow

    theholycow PlowSite.com Addict
    Messages: 1,180

    The numbers are called RPO codes and you can google for an RPO decoder where you feed them all in and see what they all mean. You can also go to compnine.com and feed in your VIN for a complete list of RPOs and their descriptions, it's less work than typing in all of the RPOs.