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rear end

Discussion in 'GM Powertrain' started by crrn204, Feb 16, 2010.

  1. crrn204

    crrn204 New Member

    I have a 2000 gmc seirra sle and need to replace the spider gears.I was wondering when I order these and they ask me if it is an 8.5 or 8.6 what they mean and also when they ask me if it is a 10 bolt.How do you tell this .

  2. MrShorty

    MrShorty Epic Member Staff Member 5+ Years 1000 Posts

    8.5 or 8.6 refers to the ring gear diameter (in inches). Both were used in the 10 bolt differential (14 bolt uses a 9.5 or something like that). I don't know what year was the cut off, but the smaller (8.5) was used in older 10 bolts, 8.6 was used in newer.

    10 bolt axles were used in half ton models, 14 bolt was used in 3/4 ton-1 ton models.

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