2 series 3 series difference

Discussion in 'Transmission & Driveline Topics' started by sandboxbob, Sep 27, 2004.

  1. sandboxbob

    sandboxbob Veteran Member

    440
    0
    Aug 19, 2004
    Florence, Arizona, USA
    How can I tell the difference between a 2 series and a 3 series 10 bolt 8.5 diff. when looking at a whole pile of them? Just the spools, I think thats what you would call them?
     
  2. 73454

    73454 Guest

    The 2 series sits 1/4" closer to the bearing on the side where the ring gear bolts on. If you were to line up the bearings of the two the one that has the ring gear land sitting furthest to the center is the 3 series. If all else fails you can use part numbers.
     
  3. badazz81z28

    badazz81z28 Veteran Member

    13,143
    42
    May 4, 2001
    Las Vegas, NV
    I would look up the part number or decode the gear ratio. a 2.73 and numrical higher will be a 3 series carrier. Watch for a spacer of sometype they have those to swap gears from one series to another. like a 3.73 on a 2 series
     
  4. big gear head

    big gear head Veteran Member

    5,785
    10
    Jul 30, 2001
    Central City, Ky.
    http://community.webshots.com/photo/55410292/55410552ePqBsq
    If you set the differential on a flat surface, like this one, you can measure from the flat surface to the surface of the ring gear flange to tell the difference. The 3 series will measure about 1.730 inches. I haven't measured a 2 series. If you are looking for a posi the 2 series has the casting number 410409 and the 3 series is number 410408.

    ------------------
    '69 RS/SS396 Pro Street
    427 4 speed 9"
    Byars Performance LLC
    High Performance Drive Train Parts And Service
    www.lubedealer.com/biggearhead
     
  5. sandboxbob

    sandboxbob Veteran Member

    440
    0
    Aug 19, 2004
    Florence, Arizona, USA
    So if I have a 2 series I could put 3.73 gears in it if I use a spacer? How strong would that be?
     
  6. badazz81z28

    badazz81z28 Veteran Member

    13,143
    42
    May 4, 2001
    Las Vegas, NV
    yes but I have no idea if it sacrafices strenght.
     
  7. big gear head

    big gear head Veteran Member

    5,785
    10
    Jul 30, 2001
    Central City, Ky.
    It won't be as strong. There are other problems with using a spacer, such as ring gear alignment.

    ------------------
    '69 RS/SS396 Pro Street
    427 4 speed 9"
    Byars Performance LLC
    High Performance Drive Train Parts And Service
    www.lubedealer.com/biggearhead
     

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