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GrudgeBox Builder's Kit

Preorder Now!

When it's time to build your transmission, we'll call you and ask about your specific configuration details (finishes, etc.). Fully paid priority orders will be built first, then the preorders that committed to $750/down.

New Generation OVERDRIVE handles over 200+HP!

Cruise at 85mph with the overdrive 6th gear; lowering RPM on the highway for improved fuel economy, reduced vibration and less wear and tear on the rider. All versions have a .92 overdrive 6th gear (250 RPM reduction).

    GrudgeBox Street Features

    • Double tapered roller main drive gear bearing, which is a much more robust setup than stock
    • Straight cut 1st, 2nd and 3rd gears for efficient torque multiplication 
    • Helical 4th, 5th and 6th gears for smooth and quiet cruising 
    • No case modifications required for installation
    • Frictionless linear detent shift system for smooth shifting
    • Redundant neutral detent to make it easy to find neutral
    • Low effort, single axis/linear motion ratchet pawl
    • More durable than stock, with 5-year 50,000 mile limited warranty


    GrudgeBox Strip  Features

    • All gears are straight cut for negligible parasitic power loss, providing maximum power transfer to the rear wheel
    • GrudgeBox Strip has wide ratio gearing for heavier performance applications
    • All other features are identical to the GrudgeBox Street version listed above

    Transmission Door Options

    GrudgeBox Standard Billet Door

    • Highlighted wrinkle black
    • Chrome
    • Special finishes available

      GrudgeBox ‘Stealth’ Door (Special Order)

      • Heavily modified stock door to retain ‘stealth’ appearance
      • Available in stock finishes only (wrinkle black or granite)

      Speedometer Reluctor Ring

      • The GrudgeBox utilizes a speedometer reluctor ring (patent pending) for sending the vehicle speed signal through the stock speed sensor, keeping the pulses per mile the same as stock.
        • 2006-later Dyna
        • 2007-later Softail & Touring

        25 Tooth Drive Sprocket: Conversion of the stock belt drive to 530 Chain is the tried and true solution to address broken belts in performance applications. 2009-later requires retrofit to earlier non cush-drive rear wheel, or aftermarket wheel, to make wheel sprocket installation possible.
        PN 25T02-07

        Cruise Drive Pulleys: Along with the launch of the Cruise Drive transmission on the 2006 Dyna models, the factory started using bigger diameter splines on the output gear. This change required us to tool up 2 new pulleys to meet the tuning needs of our performance minded customers. Pulleys are available in 31 and 30 tooth configurations. *Note* 30 tooth pulleys require the use of the 139 tooth international belt available through any major aftermarket distributor.
        PN 30T-07 (30 tooth), 31T-07 (31 tooth)

        Transmission Configurations

        • GrudgeBox Street for 2006-later Dyna and 2007-later Softail & Touring 
        • GrudgeBox Strip for wide ratio gearing for 2006-later Dyna and 2007-later Softail & Touring 

        Transmission Ratios 

         Street Strip Stock H-D
        1st–3.30 1st–3.20 1st–3.34
        2nd–2.29 2nd–2.21 2nd–2.31
        3rd–1.66 3rd–1.61 3rd–1.72
        4th–1.27 4th–1.27 4th–1.39
        5th–1.00 5th–1.00 5th–1.19
        6th–0.92 6th–0.92 6th–1.00

        Transmission Door Options 

        GrudgeBox Standard Billet Door

        • Highlighted wrinkle black
        • Chrome
        • Special finishes available 

           GrudgeBox ‘Stealth’ Door (Special Order)

          •  Heavily modified stock door to retain ‘stealth’ appearance
          • Available in stock finishes only (wrinkle black or granite) 

          Speedometer Reluctor Ring 

          The GrudgeBox utilizes a speedometer reluctor ring (patent pending) for sending the vehicle speed signal through the stock speed sensor, keeping the pulses per mile the same as stock.

            4° Undercut Shift Dogs 

          4° undercut angle on all shift dogs for positive upshift engagement.


          4° back cut angle

           Linear Detent System 

          The GrudgeBox features our frictionless linear detent shift system. The shift drum utilizes a fixed spindle design for smooth, low inertia, indexing. It’s easy to find neutral with our redundant neutral detent, which is incorporated into the architecture of the shift system.

          New Pawl Design 

          Conventional shifter pawls have a 2-point pivot system. Our new low effort single axis/linear motion shifter pawl rotates from one central pivot point, allowing continuous motion throughout the shift.

          The active plate on the shifter pawl moves up and down in line with the pawl body. This allows for smooth continuous rotation of the shifter pawl during shifts.


          NEW low effort shifter pawl movement

          Conventional shifter pawl movement

            

          PN

          Description

          Fitment

          GBST

          GrudgeBox Street, 3.30 1st gear ratio

          2006-Later Dyna, 2007-Later Softail/Touring

          GBSTR

          GrudgeBox Strip, 3.20 1st gear ratio

          Wide ratio gearing for 2007-LaterTouring

          Builder's Kit Notes: 

          -The GrudgeBox is available with a chrome or black bearing door. For a chrome bearing door add "-01" and for a black bearing door add "-03" behind the original part number. Example: GBSTR-03 is a GrudgeBox Strip version with a black bearing door.

          -There are three different shift systems available. For the standard shift system, no additional suffix is needed. For a N1 shift system, please add "-N1" to the end of the part number. For the reverse N1 pattern with ignition kill shift system, please add "-N1RK" to the end of the part number. For example, "GBSTR-01-N1" is a GrudgeBox strip version with a chrome bearing door and a N1 shift system.

          Please contact us at 517-339-3835 for more information on the NEW GrudgeBox

          Standard Gear Case Finish Examples (Not applicable to all products)

          Chrome

          Polished

          Raw

          Wrinkle Black

          These example finishes are intended to show the exterior treatments of cases, top covers and doors.

          TERM 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, transmission kits, primaries, and oil pans 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. BAKER™ clutches, kicker cover kits, belt drives, F6F kit, reverse systems, covers and accessories 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. 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 invoice of purchase. If after an evaluation has been made by BAKER™ and a defect in materials and/or workmanship is found, BAKER™  will, at BAKER™  option, repair or replace the defective part of the assembly. 

          WARRANTIES FOR "INSIDER SPECIAL" PRODUCTS

          Due to the uniqueness, low price and assembly outside of typical production process of products indicated as Insider Special products, purchasing these Insider Special products include a warranty so to guarantee the original purchaser to be free of manufacturing defects in materials and workmanship for a period of 1 year from the date of purchase or up to 12,000 miles. We have provided extended options for you to purchase below. 

          RETURNS AND EXCHANGES

          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 charges. 

          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 manufactures 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.

          The words H-D®, Softail®, FXR®, Dyna®, FLT®, FLH®, Sportster®, and Buell® are registered trademarks and are for reference only.

          Questions? Ask us anything:
          Contact us
          Or just call us at 517-339-3835. We're glad to help.

          GrudgeBox Builder's Kit
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