No announcement yet.

Dana 27 TT code deciphering

  • Filter
  • Time
  • Show
Clear All
new posts

  • Rear Axle: Dana 27 TT code deciphering

    Today I serviced the differential on my 62 Lark Daytona. It has a 259 and a Flightomatic.

    The car was assembled on October 16, 1961. The line ticket from the Studebaker National Museum does not have a line item for Twin Traction being installed from the factory, so I assume it was added by a dealer or by one of several previous owners.

    The "45B" tag identifies it as a Twin Traction, and the "27" cast into the housing identifies it as a 27 axle, but there is no 2nd tag for the gear ratio. When I removed the differential cover and rotated the tires to look for the ratio stamped on the gears, I found the following:

    11 16 61 Dana 32236 A3B55 43-13

    I'm assuming the following:

    11 16 61 is the date of manufacture, November 16, 1961
    Dana is the manufacturer
    32236 is a part number
    A3B55 is the gear ratio (3:55)
    43-13: I don't know.

    Am I correct that it has a 3:55 ratio? What do the "A" and "B" stand for in the ratio code? What does 43-13 mean?

    Thanks for your help.

    Last edited by Mark L; 08-22-2021, 09:19 PM.
    Mark L

  • #2
    43-13 is the tooth count of the crown and pinion gears, respectively. That works out to a 3.31 ratio. "45" means the ramps upon which the cross shafts rest are at a 45 degree angle. Apparently other angles did exist.
    Gord Richmond, within Weasel range of the Alberta Badlands


    • #3
      You say the car was assembled in October the think the date of rear end is November? Could be a rear end swap at some time.


      • #4
        With the Mfg. Dates THAT close, it DOES point to a Dealer installed TT to replace the Original Open one.
        Probably After the Sale and possibly before Delivery.

        Either way a 3.31 with a 259 is a fairly Peppy setup, they tend to be a bit Doggy getting started with 3.07 Gears.
        I had a '59 Lark VIII Regal 4 Door, Flight-O-Matic, that was ordered by the Parts Manager where Dad worked for Camper Trailer Towing with a 3.54, and that one WAS Quick!
        Second Generation Stude Driver,
        Proud '54 Starliner Owner
        SDC Member Since 1967


        • #5
          The car does have have a frame-mounted trailer hitch, spliced-in flat-blade trailer light hook-up, and, what appears to me, extra leaf springs. I also currently has air-adjustable rear shocks. There are no markings on the hitch, but it fits really well. Jerry Blount told me one of the previous owners in the Portland area did use it to tow a trailer.
          Mark L