BAKER 6-Into-4 OD6 Overdrive Six Speed Left Side Drive Complete Transmission for 1936 to 1986 Panhead, Knucklehead, and Shovelhead Motorcycles

The BAKER 6-into-4 is a direct replacement for the 1970 to early 1984 4-speed transmission, available with or without the time-honored 1936-1984 style kicker. It was made to satisfy the old school tendencies while providing the ability to run reasonable RPM’s at highway speeds. Panhead, Knucklehead, and Shovelhead riders will love the ability to ride hard with their friends on late model bikes. In a 4-speed transmission, 4th gear is 1:1. The BAKER 6-into-4 6-speed overdrive has a 1:1 5th gear and a .86 6th; good for a 500 RPM reduction in cruising RPM on the highway.

  • Fits 1936-1986 Panhead, Knucklehead, and Shovelhead motorcycles.

  • Available finishes are raw, wrinkle black (add $250), and show polished (add $300).

  • 5 different mainshafts are available for Knucklehead, Panhead or Shovelhead applications:
    - 1936 to 1964 length tapered mainshaft for knucklehead & panhead applications.
    - 1965 to 1969 length tapered mainshaft for panhead & shovelhead applications.
    - 1970 to early 1984 length tapered mainshaft for shovelhead applications (standard).
    - 1970 to early 1984 length splined mainshaft for shovelhead applications.
    - Late 1984 to 1986 length tapered mainshaft with diaphragm type wet clutch.

  • Case: The BAKER 6-Into-4 transmission case comes in two different versions. The 1936-1964 case has no ear, to work with the factory primary. The 1965-1986 version includes the primary ear bosses. These can be used with stock primary applications, belt drive applications, or running no primary plate at all. For the 1936-1964 Tapered Mainshaft applications, please note that the 6-into-4 case does not contain an alignment track or a provision for the primary adjustment bolt that you would normally find on a stock case.

  • 1st Gear Ratio: The 2.94 1st gear ratio fits 1936-1986 FL & FX models. This gear ratio is an all-around good ratio. The optional 3.24 1st gear ratio fits 1936-1986 FL & FX models and is recommended for heavy GVW applications. The R-Ratio 2.82 1st gear is for 1936-1986 FL & FX models and is recommended for light hot rods.

  • 2nd Gear Ratio: We recommend a 2.21 2nd gear ratio for the 2.94 and 3.24 1st gear ratios. The 2.08 2nd gear is normally paired with the 2.82 1st gear for racing applications.

  • Features include BAKER OD6-based transmission inside, many available gear ratio options, and several case, bearing door, shift system, and cover options.

  • Benefits include smooth out the rattle on the highway, and stay in the powerband.

  • Backed by a 5 year manufacturer's limited warranty from BAKER Drivetrain.

  • INSTALLATION NOTICE: The transmission bolts directly into your stock frame and your stock inner primary bolts right up. Due to the extended length of the transmission on the kicker side the exhaust pipe, oil tank and electric starter mounting brackets may have to be modified. Some inner primary covers require modification to clear the main drive nut. Some electric starter installations require modification of the transmission case for clearance. There is no speedo cable provision in the tranny case, but you can relocate the speedo cable to the front wheel. Another option is to convert over to electronic speedometer. An electronic speed sensor provision is in the door and it accepts factory 1994-later style sensors.


BAKER Builder's Kits come fully assembled
and ready to install into your existing
transmission case with no modifications,
shimming, or adjustments required.