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6-into-4 Complete Transmission

Made to satisfy the old school tendencies while providing the ability to run reasonable RPM’s at highway speeds. Panhead and Shovelhead riders will love the ability to ride hard with their friends on late model bikes.

HOW IT'S MADE

See how the 6-into-4 was exemplified as the archetypal motorcycle transmission and used as a focal point for the How It's Made television show on the Discovery Channel.

 

The bearing door will be built with a polished billet aluminum bearing door.

The top cover will be built with a polished, forged aluminum top cover with neutral switch.

 

The sprocket/pulley is not included in the complete transmission assembly. For the acquisition of these components, kindly contact BAKER Drivetrain at 517-339-3835.

  • OD6-based transmission inside
  • Many case, shift system and cover options

Benefits

  • Smooth out the rattle on the highway
  • Stay in the powerband

    Case: The 6-Into-4 Transmission case comes in two different versions. Our 1936-64 case has no ear,  to work with the factory primary. Our 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. 

    4 different mainshafts are available for Knucklehead, Panhead or Shovelhead:

    • 1936 to 1964 Tapered Mainshaft**

    • 1965 to 1969 Tapered Mainshaft

    • 1970 to E1984 Tapered Mainshaft 

    • Late 1984 to 1986 Long Tapered Mainshaft 

     

    **For 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. 

    All 6-into-4 case options come with a machined in 5th stud. We took the weakest point on other aftermarket transmissions and made it into the strongest point on ours. The 5th stud commonly breaks out of its bolted on plate causing your driveline to tweak in the chassis. The 6-Into-4 Transmission case comes in two different versions. Our 1936-64 case is a no-ear case to work with the factory primary. Our 1965-1986 version comes with the primary ear bosses on it. These can be used with stock primary applications, belt drive applications, or running no primary plate at all. Both cases have a provision for an electronic speedometer. The electronic speedometer would utilize a stock 1996-2006 speed sensor, PN 74437-96. Pending what type of electronic speedometer you use, an additional speedometer recalibration box might have to be purchased, BAKER PN 95E-56B. The BAKER 6-into-4 case does not have a gear drive speedometer cable provision on the case. 

    • Late 1984-1986 length mainshaft.  Diaphragm type wet clutch.

    • 1970-Early 1984 length mainshaft.  Shovelhead mainshaft.

    • 1965-1969 length mainshaft.  Panhead/Shovelhead.

    • 1936-1964 length mainshaft.  Knuckle/Panhead mainshaft.    

    Shift Drum Options

    • Standard Drum Shift Pattern (1-N-2-3-4-5-6 shift pattern)

    • N1 Drum Shift Pattern (N-1-2-3-4-5-6 shift pattern)

    Klassic Kicker Gears

    Kicker Gears All BAKER 6-into-4s come standard with our Klassic Kicker Gears. Made out of 1018 HR Steel, tumble finished to around a 20 micro and heat-treated to 50-55 RC; these gears roll smooth as glass. 

    Kicker Cover Options

    We manufacture and offer 3 different kicker covers making the 6-into-4 completely customizable from stock to custom build. Depending on the choice of cover and finish, additional charges may apply.  

    The 6-into-4 comes standard with a straight kick arm.

    Top Cover Options

    The 6-into-4 comes standard with a single-pole neutral switch top cover with our hidden vent.  The transmission can be ordered with our no-neutral top cover.

    Gear Ratios

    Standard

    Ratios

    1st Gear

    2.94

    2nd Gear

    2.21

    3rd Gear

    1.60

    4th Gear

    1.23

    5th Gear

    1.00

    6th Gear

    .86

     

    Note

    Each transmission is hand-built to order.

    Sprocket: 6-into-4 has 2 more gears than a 4-speed and sticks out 1.6” more. The rear exhaust pipe, oil tank brackets, and starter brackets may have to be modified for fitment.

    – Electric speed sensor provision in case accepts stock 1994-up speed sensors.

    – Some 1970s inner primaries may require modification for sprocket nut clearance.

    Recommended Exhausts 

    With the factory exhaust not fitting in most cases, you will need to make sure that you find an exhaust that goes around the side cover. The 6-into-4 has 2 more gears than a 4-speed and sticks out 1.6” more.

    Recommended Fluid / Level

    Picking the right transmission fluid ensures the life and durability of your transmission, that’s why BAKER recommends a fully synthetic GL-5 rated gear weight oil of 75W-140. If a GL-5 rated gear lube is not available, these commonly carried viscosities (weights) will work: 75W-90, 75W-140, and 85W-140. BAKER does not recommend the use of Syn3 (20W-50).

    For Bert’s  article on ‘Oil & Spiders’  Click Here  

    BAKER 6-into-4 Fluid Capacity Dry: 22-24fl-oz BAKER 6-into-4 Fluid Capacity Wet: 18-22fl-oz   

    Learn more about Spectro Performance Oils here: https://spectro-oils.com

    Instructions

     

     BAKER 6-into-4 install instructions with exploded views

     

     

    TERMS AND CONDITIONS

    BAKER Drivetrain reserves the right to change prices, terms or policies at any time without notice. Orders can be pre-paid using Visa, MasterCard, American Express, Discover or PayPal. All orders not pre-paid will be sent C.O.D. certified check or money order only unless pre-approved for company check acceptance. Any orders from outside the USA must be pre-paid in US funds via wire transfer; a $30 transfer fee will apply. Prices shown are F.O.B. Haslett, MI.

    LIMITED WARRANTY POLICY

    BAKER™ transmission assemblies and transmission builder 's kits, are guaranteed to the original purchaser to be free of manufacturing defects in materials and workmanship for a period of 5 years from the date of purchase or up to 50,000 miles, whichever occurs first. All other BAKER products are guaranteed to the original purchaser to be free of manufacturing defects in materials and workmanship for a period of 2 years from the date of purchase or up to 24,000 miles, whichever occurs first, except for the following; Warranty does not cover clutch plate wear, throw out bearing failures or mainshaft breakage due to improper clutch nut installation.Electrical components carry a 30-day warranty; cosmetic finishes (chrome plating, hard anodizing, powder coating) are covered for 60 days. Certain promotional products may carry a shorter warranty as specified at the time of purchase. If the product is found by BAKER to be defective, such products will, at the option of BAKER, be replaced or repaired at cost to BAKER.In the event warranty service is required, the original purchaser must call or write BAKER immediately with a description of the problem. If it is deemed necessary for BAKER to make an evaluation to determine whether the transmission assembly or transmission kit or accessory is defective, the entire transmission assembly, whether originally purchased as an assembly or kit, must be properly packaged and returned prepaid to BAKER with a copy of the original purchase invoice. If after evaluation by BAKER a defect in materials and/or workmanship is found, BAKER will, at their option, repair or replace the defective part of the assembly.

    RETURNS AND EXCHANGES

    Returns are permitted within 30 days of the delivery date. Any merchandise returned for any reason (exchange, credit or modification) must be accompanied by a Return Goods Authorization (RGA) number or it will be refused. Call BAKER to obtain this number prior to returning goods for any reason. There is a 15% re-stocking fee for all returned items. BAKER is not liable for any shipping.

    ADDITIONAL WARRANTY PROVISIONS

    NOTE: Limited warranty does not cover labor or other costs or expenses incidental to the repair and or replacement of BAKER products.This warranty does not apply if one or more of the following situations is judged by BAKER to be relevant: BAKER OEM transmissions ; (these are subject to the OEM manufacturers warranty only), Improper installation , accident, modification (including but not limited to use of unauthorized parts, transmission oils or lubricants), racing, high performance application, mishandling, misapplication, neglect (including but not limited to improper maintenance), or improper repair. BAKER shall not be liable for any consequential or incidental damages arising out of or in connection with a BAKER transmission assembly, transmission kit, component or part. Consequential damages shall include without limitation, loss of use, income or profit, or losses sustained as the result of injury (including death) to any person or loss of or damage to property.BAKER transmissions, transmission kits and accessories are designed exclusively for use in American V-Twin motorcycles. BAKER shall have no warranty or liability obligation if BAKER parts are used in any other application.If it is determined that a BAKER product has been disassembled during the warranty period for any reason, this limited warranty will no longer apply unless you were instructed to do so by a BAKER Drivetrain technician for diagnostic purposes.



    6-into-4 transmission for Knucklhead, Panhead and Shovelhead 1936-1984 Harley-Davidson
    Move your mouse over image to zoom. Click to enlarge.
    6-into-4 transmission for Knucklhead, Panhead and Shovelhead 1936-1984 Harley-Davidson 6-into-4 transmission for Knucklhead, Panhead and Shovelhead 1936-1984 Harley-Davidson 6-into-4 transmission for Knucklhead, Panhead and Shovelhead 1936-1984 Harley-Davidson 6-into-4 transmission for Knucklhead, Panhead and Shovelhead 1936-1984 Harley-Davidson 6-into-4 transmission for Knucklhead, Panhead and Shovelhead 1936-1984 Harley-Davidson 6-into-4 transmission for Knucklhead, Panhead and Shovelhead 1936-1984 Harley-Davidson 6-into-4 transmission for Knucklhead, Panhead and Shovelhead 1936-1984 Harley-Davidson 6-into-4 transmission for Knucklhead, Panhead and Shovelhead 1936-1984 Harley-Davidson 6-into-4 transmission for Knucklhead, Panhead and Shovelhead 1936-1984 Harley-Davidson 6-into-4 transmission for Knucklhead, Panhead and Shovelhead 1936-1984 Harley-Davidson
    Customer Reviews
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    Filter Reviews:
    • Baker
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    • American
    CV
    08/28/2023
    Caspar v.
    France France
    • What model motorcycle do you ride? home build rigid 1974 shovelhead

    a must

    Installed the 6 into 4 nearly twenty years ago on my home-build rigid shovelhead. Rode all around Europe and made more than 120.000miles. It still runs like new and it was for me the best investment I ever made on my bike. Thanks Baker, you're a legend! Cheers from France

    BAKER Drivetrain 6-into-4 Complete Transmission ReviewBAKER Drivetrain 6-into-4 Complete Transmission Review
    DK
    06/30/2023
    David K.
    Australia Australia
    • What model motorcycle do you ride? Various Harley Davidson

    6-into-4 Complete Transmission

    Great Support & Correspondence

    RL
    02/10/2023
    Ron L.
    United States United States
    • What model motorcycle do you ride? Santee rigid, SS 93” EVO/Shovel

    Service

    Thank KP! Received the early model 4 speed hydraulic kicker cover this week. Will continue with the overhaul. I greatly appreciate the help to identify the parts needed and quick response.

    BAKER Drivetrain 6-into-4 Complete Transmission Review
    RJ
    12/01/2022
    Robert J.
    United States United States
    • What model motorcycle do you ride? 1973 FLH , 2019 Roadglide , 1996 FLSTN

    6 into 4 Ass Kicker

    I believe Baker has the best transmissions on the market !! American made as well !!

    CB
    11/15/2022
    Charles B.
    United States United States
    • What model motorcycle do you ride? '79 Shovelhead

    Coolest tranny since a tranny was a tranny.

    Have wanted a 6 speed in the Shovelhead for a long time, finally decided to make it happen. It's winter time in Wyoming, good time to fix a few things on the bike. Looking forward to warmer weather, clear roads & banging through 6 gears. Very nice transmission & excellent customer service!

    Web Product ID: 4682374787
    Baker Drivetrain Team Illustration

    Made to satisfy the old school tendencies while providing the ability to run reasonable RPM’s at highway speeds. Panhead and Shovelhead riders will love the ability to ride hard with their friends on late model bikes.

    HOW IT'S MADE

    See how the 6-into-4 was exemplified as the archetypal motorcycle transmission and used as a focal point for the How It's Made television show on the Discovery Channel.

     

    The bearing door will be built with a polished billet aluminum bearing door.

    The top cover will be built with a polished, forged aluminum top cover with neutral switch.

     

    The sprocket/pulley is not included in the complete transmission assembly. For the acquisition of these components, kindly contact BAKER Drivetrain at 517-339-3835.

    • OD6-based transmission inside
    • Many case, shift system and cover options

    Benefits

    • Smooth out the rattle on the highway
    • Stay in the powerband

      Case: The 6-Into-4 Transmission case comes in two different versions. Our 1936-64 case has no ear,  to work with the factory primary. Our 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. 

      4 different mainshafts are available for Knucklehead, Panhead or Shovelhead:

      • 1936 to 1964 Tapered Mainshaft**

      • 1965 to 1969 Tapered Mainshaft

      • 1970 to E1984 Tapered Mainshaft 

      • Late 1984 to 1986 Long Tapered Mainshaft 

       

      **For 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. 

      All 6-into-4 case options come with a machined in 5th stud. We took the weakest point on other aftermarket transmissions and made it into the strongest point on ours. The 5th stud commonly breaks out of its bolted on plate causing your driveline to tweak in the chassis. The 6-Into-4 Transmission case comes in two different versions. Our 1936-64 case is a no-ear case to work with the factory primary. Our 1965-1986 version comes with the primary ear bosses on it. These can be used with stock primary applications, belt drive applications, or running no primary plate at all. Both cases have a provision for an electronic speedometer. The electronic speedometer would utilize a stock 1996-2006 speed sensor, PN 74437-96. Pending what type of electronic speedometer you use, an additional speedometer recalibration box might have to be purchased, BAKER PN 95E-56B. The BAKER 6-into-4 case does not have a gear drive speedometer cable provision on the case. 

      • Late 1984-1986 length mainshaft.  Diaphragm type wet clutch.

      • 1970-Early 1984 length mainshaft.  Shovelhead mainshaft.

      • 1965-1969 length mainshaft.  Panhead/Shovelhead.

      • 1936-1964 length mainshaft.  Knuckle/Panhead mainshaft.    

      Shift Drum Options

      • Standard Drum Shift Pattern (1-N-2-3-4-5-6 shift pattern)

      • N1 Drum Shift Pattern (N-1-2-3-4-5-6 shift pattern)

      Klassic Kicker Gears

      Kicker Gears All BAKER 6-into-4s come standard with our Klassic Kicker Gears. Made out of 1018 HR Steel, tumble finished to around a 20 micro and heat-treated to 50-55 RC; these gears roll smooth as glass. 

      Kicker Cover Options

      We manufacture and offer 3 different kicker covers making the 6-into-4 completely customizable from stock to custom build. Depending on the choice of cover and finish, additional charges may apply.  

      The 6-into-4 comes standard with a straight kick arm.

      Top Cover Options

      The 6-into-4 comes standard with a single-pole neutral switch top cover with our hidden vent.  The transmission can be ordered with our no-neutral top cover.

      Gear Ratios

      Standard

      Ratios

      1st Gear

      2.94

      2nd Gear

      2.21

      3rd Gear

      1.60

      4th Gear

      1.23

      5th Gear

      1.00

      6th Gear

      .86

       

      Note

      Each transmission is hand-built to order.

      Sprocket: 6-into-4 has 2 more gears than a 4-speed and sticks out 1.6” more. The rear exhaust pipe, oil tank brackets, and starter brackets may have to be modified for fitment.

      – Electric speed sensor provision in case accepts stock 1994-up speed sensors.

      – Some 1970s inner primaries may require modification for sprocket nut clearance.

      Recommended Exhausts 

      With the factory exhaust not fitting in most cases, you will need to make sure that you find an exhaust that goes around the side cover. The 6-into-4 has 2 more gears than a 4-speed and sticks out 1.6” more.

      Recommended Fluid / Level

      Picking the right transmission fluid ensures the life and durability of your transmission, that’s why BAKER recommends a fully synthetic GL-5 rated gear weight oil of 75W-140. If a GL-5 rated gear lube is not available, these commonly carried viscosities (weights) will work: 75W-90, 75W-140, and 85W-140. BAKER does not recommend the use of Syn3 (20W-50).

      For Bert’s  article on ‘Oil & Spiders’  Click Here  

      BAKER 6-into-4 Fluid Capacity Dry: 22-24fl-oz BAKER 6-into-4 Fluid Capacity Wet: 18-22fl-oz   

      Learn more about Spectro Performance Oils here: https://spectro-oils.com

      Instructions

       

       BAKER 6-into-4 install instructions with exploded views

       

       

      TERMS AND CONDITIONS

      BAKER Drivetrain reserves the right to change prices, terms or policies at any time without notice. Orders can be pre-paid using Visa, MasterCard, American Express, Discover or PayPal. All orders not pre-paid will be sent C.O.D. certified check or money order only unless pre-approved for company check acceptance. Any orders from outside the USA must be pre-paid in US funds via wire transfer; a $30 transfer fee will apply. Prices shown are F.O.B. Haslett, MI.

      LIMITED WARRANTY POLICY

      BAKER™ transmission assemblies and transmission builder 's kits, are guaranteed to the original purchaser to be free of manufacturing defects in materials and workmanship for a period of 5 years from the date of purchase or up to 50,000 miles, whichever occurs first. All other BAKER products are guaranteed to the original purchaser to be free of manufacturing defects in materials and workmanship for a period of 2 years from the date of purchase or up to 24,000 miles, whichever occurs first, except for the following; Warranty does not cover clutch plate wear, throw out bearing failures or mainshaft breakage due to improper clutch nut installation.Electrical components carry a 30-day warranty; cosmetic finishes (chrome plating, hard anodizing, powder coating) are covered for 60 days. Certain promotional products may carry a shorter warranty as specified at the time of purchase. If the product is found by BAKER to be defective, such products will, at the option of BAKER, be replaced or repaired at cost to BAKER.In the event warranty service is required, the original purchaser must call or write BAKER immediately with a description of the problem. If it is deemed necessary for BAKER to make an evaluation to determine whether the transmission assembly or transmission kit or accessory is defective, the entire transmission assembly, whether originally purchased as an assembly or kit, must be properly packaged and returned prepaid to BAKER with a copy of the original purchase invoice. If after evaluation by BAKER a defect in materials and/or workmanship is found, BAKER will, at their option, repair or replace the defective part of the assembly.

      RETURNS AND EXCHANGES

      Returns are permitted within 30 days of the delivery date. Any merchandise returned for any reason (exchange, credit or modification) must be accompanied by a Return Goods Authorization (RGA) number or it will be refused. Call BAKER to obtain this number prior to returning goods for any reason. There is a 15% re-stocking fee for all returned items. BAKER is not liable for any shipping.

      ADDITIONAL WARRANTY PROVISIONS

      NOTE: Limited warranty does not cover labor or other costs or expenses incidental to the repair and or replacement of BAKER products.This warranty does not apply if one or more of the following situations is judged by BAKER to be relevant: BAKER OEM transmissions ; (these are subject to the OEM manufacturers warranty only), Improper installation , accident, modification (including but not limited to use of unauthorized parts, transmission oils or lubricants), racing, high performance application, mishandling, misapplication, neglect (including but not limited to improper maintenance), or improper repair. BAKER shall not be liable for any consequential or incidental damages arising out of or in connection with a BAKER transmission assembly, transmission kit, component or part. Consequential damages shall include without limitation, loss of use, income or profit, or losses sustained as the result of injury (including death) to any person or loss of or damage to property.BAKER transmissions, transmission kits and accessories are designed exclusively for use in American V-Twin motorcycles. BAKER shall have no warranty or liability obligation if BAKER parts are used in any other application.If it is determined that a BAKER product has been disassembled during the warranty period for any reason, this limited warranty will no longer apply unless you were instructed to do so by a BAKER Drivetrain technician for diagnostic purposes.