Data gathering for regearing -- some assistance?

Discussion in 'GM Powertrain' started by SurrealOne, Nov 25, 2011.

  1. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    Here's what I know:
    • Year, Make, & Model: 2004 GMC Sierra 1500 Ext Cab 4x4 w/ 96" Bed
    • Tire size: 315/70R17
    • Original Gear Ratio: 3.73 (RPO Code GT4 = Axle Rear (DUP WITH 5 X 1) 3.73)
    • Desired Gear Ratio: 4.56
    • Number of Cover Bolts: 10 bolt (11 inches wide - i.e. has GM 8.2 or 8.5 ring gear diameter, but not sure which)
    • Transmission Type: 4L60E
    • Engine Size: 5.3L
    • Desired Highway Cruise Engine RPM: ~2000
    • Number of Wheel Lugs: 6
    • Suspension Type: Independent Front
    Here's what I need to know (ideally without any disassembly, as I'm merely information gathering in order to cost out parts) and don't know how to find out:
    • Axle spline Count?
    • Actual Ring Gear Diameter (8.2" or 8.5")?
    • Number of Ring Gear Bolts?
    • Dana Bill of Material Number or Tag Numbers (if applicable)?
    • Standard or Reverse Rotation Front Ring & Pinion?
    • Axle Bearing Outer Diameter?
    Can anyone point me in the right direction(s)?
    Last edited: Nov 25, 2011
  2. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    This data is what needs to be collected prior to ordering parts for regearing. Colour me VERY surprised that we have so many people who have regeared ... and no one ordered his/her own parts.

    TELORVEHC Rockstar 4 Years 1000 Posts

  4. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts


    99'HEARTBEAT MODERATOR Staff Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor

    To help with some of your questions on your 2004" Sierra with 3.73's,
    .....Axle spline Count......30
    .....Actual Ring Gear Diameter........8.625

    .....Number of Ring Gear Bolts......10/Bolts

    .....Standard or Reverse Rotation Front Ring & Pinion.......Standard

  6. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    Wow, thanks! Where did you get this data if you don't mind me asking? I'd like to know where it came from so that I don't just walk away with my answer ... but I also walk away a little more educated/capable ... such that I can help the next guy who comes along.

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