Ford S6-650 Transmission

Ford Grill

Convert your Ford S6-650 to an Allison

Transform Your Drive: Making the Switch to an Allison 1000PK Transmission

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Unleash the full potential of your heavy-duty vehicle with a Ford S6-650 to Allison 1000PK transmission conversion. Known for its exceptional strength and efficiency, the Allison 1000PK transmission has been engineered to deliver unparalleled performance, even in the toughest driving conditions. This conversion not only upgrades your truck with a more robust and responsive transmission, but also enhances its longevity, making it a smart investment for those seeking to optimize their vehicle's capabilities. Whether you’re hauling heavy loads or navigating challenging terrains, this upgrade promises a smoother, more controlled, and remarkably reliable driving experience – it's the powerful and precise solution that your Ford S6-650 has been waiting for.

4R100 Transmission: An Overview, Key Features, and Common Concerns

Overview of the 4R100 Transmission

The Ford S6-650 is a heavy-duty manual transmission designed and manufactured by Ford Motor Company. Introduced in the early 2000s, this six-speed manual transmission is revered by truck owners for its exceptional strength and high torque capacity. Primarily engineered for Ford trucks, such as the F-250, F-350, and F-450 Super Duty models, the S6-650 is paired with Power Stroke diesel engines or Triton gas engines, creating a robust and reliable powertrain combination. With a reputation for standing up to severe usage conditions, the S6-650 has become the go-to for heavy towing and demanding work environments.

Featuring a synchronized gear set and dual countershafts, the S6-650 is constructed to provide smooth and precise shifting that enhances both performance and driver control. Its rugged iron case and extensive use of roller bearings speak to its durability and functionality. This transmission is designed with a wide range of gear ratios, ensuring it is capable of massive towing and payload capacities, while still enabling comfortable and fuel-efficient highway cruising.

However, as automotive industry trends have moved towards more gears and increasingly refined automatic transmissions, the S6-650 has come to symbolize a past generation of technology. It appeals to a specific kind of driver—those who appreciate the tactile control and straightforward nature of a classic, sturdy manual transmission. For these individuals, the S6-650 remains a beloved and trusted choice.

S6-650 Features

The S6-650 transmission is a workhorse designed for heavy-duty Ford trucks. Notable for its ruggedness and high torque capacity, here are some key features that make the S6-650 stand out:

  • High Torque Capacity: Engineered for heavy-duty applications, the S6-650 is designed to handle extreme levels of torque, making it perfect for towing and hauling significant loads.
  • Synchronized Gears: The S6-650 features synchronized gears, ensuring smooth and precise shifting under various operating conditions.
  • Durable Construction: With a rugged iron case and robust internal components, the S6-650 is constructed to withstand the rigorous demands of heavy-duty truck use.
  • Wide Gear Ratio Spread: The S6-650 offers a broad range of gear ratios, facilitating strong towing capacity and fuel-efficient highway cruising.
  • Direct Drive Capability: This feature enhances fuel efficiency and power transfer, making for a more responsive driving experience.
  • Adaptable to Aftermarket Upgrades: Given its longstanding popularity, a vibrant aftermarket exists for the S6-650, offering parts and upgrade options for those looking to further enhance the transmission’s performance.

In summary, the S6-650 is a robust, reliable, and versatile manual transmission designed to handle the intense demands of heavy-duty truck applications. Its features are crafted to provide drivers with remarkable towing capacity and enduring performance under a wide variety of conditions.

S6-650 Common Issues and Signs of Failures

While the S6-650 transmission is celebrated for its strength and heavy-duty performance, like any mechanical component, it can have its issues. Here are some common problems associated with the S6-650 transmission, along with signs that it might be failing:

  • Gear Synchronizer Wear: Over time, the synchronizers, which enable smooth gear changes, can wear out, leading to grinding or hard shifting.
  • Bearing Failures: The bearings in the S6-650 may fail due to heavy loads or lack of lubrication, resulting in noise and potential damage.
  • Clutch Problems: Being a manual transmission, clutch issues, such as slippage or difficulty engaging gears, can occur with the S6-650.
  • Input Shaft Wear: Heavy towing can put stress on the input shaft, leading to wear and potential failure.
  • Seal and Gasket Leaks: Over time, the seals and gaskets may degrade, leading to fluid leaks and potential internal damage.

Regular maintenance, including proper fluid changes and timely replacement of worn components, can significantly extend the life of an S6-650 transmission and prevent many of these issues.

When experiencing any of these symptoms, it is advisable to consult with a professional mechanic or transmission specialist to diagnose and address the problem before it leads to a complete transmission failure.

Your Guide to Rebuilding, Replacing, and Upgrading to an Allison Transmission

Rebuild, Replace, Converting to an Allison

Convert to Allison

Converting to an Allison 1000PK Transmission

Transitioning from the Ford S6-650 manual transmission to an Allison 1000PK automatic transmission is an intricate procedure that demands meticulous attention to detail, the right tools, and a deep understanding of both transmission systems. This guide outlines the steps required for a successful conversion:

  1. Research and Planning

    • Determine the feasibility of integrating the Allison 1000PK with your specific engine and chassis configuration.
    • Identify any specialized conversion kits or parts available for this specific transmission swap.
    • Prepare a detailed list of tools, parts, and any specialized equipment required for the conversion.
  2. Acquire Necessary Parts

    • Procure the Allison 1000PK transmission unit.
    • Secure a compatible bell housing or an adapter plate to link the Allison transmission to your engine.
    • Purchase the Transmission Control Module (TCM) suitable for the Allison 1000PK.
    • Obtain necessary wiring harnesses, electrical connectors, and adapters specific to this conversion.
    • Ensure availability of a transmission cooler compatible with the Allison 1000PK’s requirements.
  3. Removal of S6-650 Transmission

    • Disconnect the vehicle's battery.
    • Empty the transmission fluid from the S6-650.
    • Unlink the transmission linkage, driveshaft, and any pertinent electrical or hydraulic connections.
    • Carefully extract the S6-650 transmission from the vehicle.
  4. Preparation and Modification

    • Inspect and, if necessary, adjust the vehicle’s transmission tunnel to ensure adequate fitment for the Allison 1000PK.
    • Replace or modify any incompatible motor mounts, crossmembers, or transmission supports to ensure a stable fit.
  5. Install the Allison 1000PK

    • Utilizing a transmission jack, carefully position and align the Allison 1000PK to the engine, ensuring correct fitment with the bell housing or adapter plate.
    • Secure all connections, including any required mechanical linkages or hydraulic lines.
  6. Electronics and Wiring

    • Install the TCM in a strategic location, ensuring minimal exposure to external elements.
    • Connect the wiring harness, ensuring all connectors are properly secured and protected from potential damage or wear.
    • Integrate the Allison's electronic components seamlessly with the existing vehicle electrical infrastructure, verifying that the TCM and engine control unit (ECU) are in proper communication.
  7. Cooling System Installation

    • Fit the transmission cooler in an optimal location to facilitate efficient cooling.
    • Connect the cooling lines between the Allison 1000PK and the designated cooler, ensuring a leak-free connection.
  8. Drive Shaft and Final Connections

    • If necessary, adjust the current driveshaft's length or consider a custom-made alternative to ensure compatibility with the new transmission setup.
    • Fit the driveshaft, guaranteeing proper alignment and secure connections on both ends.
  9. Fluids and Testing

    • Refill the Allison 1000PK transmission with the manufacturer-recommended transmission fluid.
    • Reconnect the vehicle's battery.
    • Initiate the vehicle, testing all gear positions for accurate function and response.
    • Perform a comprehensive test drive to confirm the transmission’s smooth operation and ensure the TCM’s correct behavior.
  10. Final Adjustments

    • Post-test drive, examine the entire system for any leaks, noises, or inconsistencies.
    • If necessary, recalibrate or adjust linkages, electrical components, or other associated parts for optimal operation.

Documentation and Compliance:

  • Retain a record of all modifications, part replacements, and adjustments for future reference and potential resale purposes.
  • Always consult local and regional regulations to ensure your conversion adheres to all safety, emissions, and other pertinent legal guidelines.

Given the intricacy of such a conversion, it’s paramount to collaborate with seasoned professionals, especially those familiar with transmission swaps between distinct brands or models. When executed correctly, this conversion can harness the robustness and efficiency of the Allison 1000PK, enhancing your vehicle's overall performance and driving experience.

S6-650 Rebuild

Rebuilding the Ford S6-650 Transmission: A Comprehensive Guide

The Ford S6-650 is a heavy-duty manual transmission known for its durability and strength. However, like any mechanical component, it may require a rebuild after extensive use. Rebuilding a transmission is a detailed and meticulous task, so patience, organization, and proper knowledge are essential. This step-by-step guide outlines the process to rebuild the S6-650 transmission:

  1. Preparation and Assessment

    • Review the S6-650 service manual for specifications, tolerances, and procedures.
    • Inspect the transmission for signs of wear, noting specific areas that may require special attention during the rebuild.
    • Compile a list of necessary tools, parts, and any specialized equipment needed for the rebuild.
  2. Acquire Necessary Parts

    • Purchase a complete rebuild kit, which typically includes bearings, seals, gaskets, and synchronizers.
    • Source any additional replacement parts as needed, based on the initial assessment of the transmission's condition.
  3. Transmission Removal

    • Disconnect the vehicle's battery.
    • Remove the transmission from the vehicle, following proper safety protocols and noting how components are connected for reassembly.
  4. Disassembly and Cleaning

    • Disassemble the transmission systematically, placing parts in organized containers and taking photos to aid reassembly.
    • Clean all parts with a solvent and inspect for wear and damage. Discard components that are beyond repair.
  5. Component Inspection and Replacement

    • Thoroughly examine gears, bearings, synchros, and other internal components for wear.
    • Replace worn components with new parts from the rebuild kit or additional parts sourced separately.
  6. Reassembly

    • Using your photos and service manual as guides, reassemble the transmission, ensuring each component is installed correctly and torqued to specifications.
    • Install new seals, gaskets, and bearings as you go, ensuring that all parts move freely without binding.
  7. Testing and Quality Control

    • Rotate the transmission’s input and output shafts to ensure they turn smoothly and that all gears engage properly.
    • Inspect for any leaks from the newly installed seals and gaskets.
  8. Reinstallation into Vehicle

    • Carefully reinstall the rebuilt transmission into the vehicle, reconnecting all linkages, cables, and electrical connections as necessary.
    • Refill the transmission with the recommended fluid to the proper level.
  9. Final Testing and Adjustment

    • Reconnect the vehicle's battery and start the engine, then conduct a thorough test drive to ensure all gears engage smoothly and the transmission operates quietly and efficiently.
    • Make any necessary adjustments, such as clutch linkage or shift cables, for optimal performance.

Documentation and Compliance:

  • Retain a record of all replaced parts, adjustments, and any issues encountered during the rebuild for future reference and potential resale purposes.
  • Always consult the service manual and follow all recommended procedures and safety precautions to ensure a successful and safe rebuild.

Rebuilding a transmission, especially one as robust as the S6-650, can be a rewarding project that significantly extends the life of your vehicle’s drivetrain. However, it is a complex task that requires mechanical skill, patience, and meticulous attention to detail. It is often beneficial to seek assistance from a professional mechanic, especially if you are undertaking a project of this magnitude for the first time.

Replace 4R100

Replacing the Ford S6-650 Transmission: A Comprehensive Guide

Replacing the Ford S6-650 transmission involves removing the old unit and installing a new or remanufactured one. This procedure demands meticulous care, the right tools, and a solid understanding of transmission systems. This step-by-step guide outlines the process of replacing the S6-650 transmission:

  1. Preparation and Assessment

    • Research and confirm the specifications of the replacement transmission and ensure it is compatible with your vehicle.
    • Compile a list of necessary tools and any specialized equipment needed for the job.
  2. Acquire a Replacement Transmission

    • Purchase a new or remanufactured S6-650 transmission from a reputable source.
    • Consider acquiring a warranty for the replacement unit, if available.
  3. Transmission Removal

    • Disconnect the vehicle's battery.
    • Remove the old S6-650 transmission from the vehicle, following proper safety protocols.
  4. Inspect and Prepare the New Transmission

    • Inspect the new or remanufactured transmission for any shipping damage or defects.
    • Prepare the unit for installation by ensuring it is clean and applying any necessary lubrication to moving parts and seals.
  5. Install the Replacement Transmission

    • Position the replacement S6-650 transmission into the vehicle using a transmission jack.
    • Bolt the transmission to the engine, ensuring all connections are secure and torqued to specifications.
    • Reconnect any mechanical linkage, hydraulic lines, and electrical connections, if applicable.
  6. Reconnect Drivetrain Components

    • Reinstall the driveshaft, ensuring it is correctly aligned and securely connected at both ends.
    • Reconnect any additional components removed during the process, such as crossmembers and exhaust parts.
  7. Refill Transmission Fluid and Complete Connections

    • Fill the new S6-650 transmission with the recommended transmission fluid to the proper level.
    • Reconnect the vehicle's battery and complete any remaining electrical connections.
  8. Testing and Quality Control

    • Start the vehicle and check for any leaks or abnormal noises.
    • Engage all gears to ensure they are working smoothly and the clutch (if manual) is engaging correctly.
    • Conduct a thorough test drive to confirm that the transmission operates as expected under various conditions.
  9. Final Adjustments and Inspection

    • After the test drive, reinspect for leaks or irregularities and make any necessary adjustments.
    • Check and adjust fluid levels as necessary after the transmission has reached its normal operating temperature.

Documentation and Compliance:

  • Maintain a record of the replacement, including the source of the new transmission, date of installation, and any issues encountered for future reference and potential resale purposes.
  • Ensure that the replacement process adheres to any applicable warranties, laws, or regulations.

Replacing a transmission is a significant undertaking that requires mechanical skill and meticulous attention to detail. While it is possible for a skilled DIY mechanic to complete this project, it may be beneficial to seek assistance from a professional mechanic to ensure that the job is done correctly and safely.

Benefits of converting to an Allison 1000PK Transmission

Converting to the Allison 1000PK transmission can offer a significant improvement in the performance, durability, and efficiency of a vehicle. Known for its use in a wide range of applications, from light-duty trucks to heavy-duty commercial vehicles, the Allison 1000PK is a trusted choice for many looking to upgrade their transmission system. Below are some key benefits of making the conversion:

Enhanced Durability and Reliability

Allison transmissions, including the 1000PK series, are renowned for their durability and longevity. They are designed to handle heavy loads and demanding conditions, reducing the likelihood of frequent repairs and breakdowns, which makes the Allison 1000PK a long-lasting solution.

Improved Towing and Hauling Capabilities

The Allison 1000PK provides superior torque and power handling, allowing for more efficient and safer towing and hauling. Whether you are pulling a large trailer, boat, or other heavy loads, this transmission can help your vehicle perform at its best under strenuous conditions.

Smooth and Adaptive Shifting

With its sophisticated control system and efficient design, the Allison 1000PK can contribute to better fuel economy. By optimizing shift points based on load, speed, and other factors, it helps the engine run in the most efficient range, potentially saving fuel over time.

Lower Maintenance Costs

The robust design and high-quality components used in the Allison 1000PK often result in lower maintenance costs over time. Its proven durability under various conditions can lead to fewer required repairs and service intervals, translating to long-term cost savings.

Versatility and Compatibility

The Allison 1000PK is designed to be compatible with a wide range of vehicles and applications. This makes it a versatile option for those looking to upgrade their transmission in various types of vehicles, from light trucks to commercial applications.

Resale Value

Installing a well-regarded and reliable transmission like the Allison 1000PK can increase the resale value of your vehicle. Buyers often appreciate the quality and dependability associated with Allison transmissions, which can make your vehicle more attractive on the resale market.

What's included in an Allison Conversion kit?

We provide everything you will need to get the swap done right

Duramax with Allison Transmission
    • Kit Includes
    • Transmission
      Torque Converter
      Wiring Harness
      Flex Plate adapter
      Transfer Case
      Mounting Kit
      Cooling Kit
      Digital Display
      Allison TCM
      CAC TCM
Allison 1000PK Transmission

Allison 1000PK Transmission

Upgrade your vehicle's capabilities with the esteemed Allison 1000PK Transmission. You have the option to either include this component in your kit purchase or use your own pre-acquired Allison 1000PK transmission. To cater to your needs, we also provide transmission rebuilding services. Explore a comprehensive selection of other Allison transmissions here that we can expertly convert.

How to determine the Right Torque Converter

Maximizing Performance: Using Tire Diameter and Gear Ratio Calculations to Choose the Ideal Torque Converter

How to determine the right torque converter


By converting your Ford's transmission to an Allison, you can expect improved durability, enhanced towing capability, better fuel efficiency, and smoother shifts, overall optimizing your vehicle's performance.

While many Ford vehicles can benefit from an Allison transmission conversion, it's best to consult with a specialist to ensure your specific model's compatibility.

Yes, with our t-case adapters, you can use your existing Ford transfer case in an Allison conversion.

The Allison 1000 series is a popular choice for Ford vehicles due to its reliability and performance. However, the best choice depends on your specific needs and vehicle model.

The conversion process involves removing your Ford's current transmission, fitting the Allison transmission with the necessary adapters, and installing it. The wiring harness, TCM, and other components are also adjusted accordingly.

Yes, an Allison transmission is designed to provide smoother shifts, greater durability, and improved fuel efficiency, all contributing to enhanced vehicle performance.

An Allison conversion kit typically includes components such as the transmission (if chosen), TCM, torque converter, wiring harness, adapters, and other necessary parts for the conversion.

You can choose to provide your own Allison transmission, or you can opt to include it with your conversion kit purchase.

While it's possible for experienced individuals to perform the conversion, it's generally recommended to seek professional help to ensure the job is done correctly and safely.

The conversion time can vary greatly depending on the vehicle and the specific conversion kit. On average, it might take a few days to complete.

An Allison conversion may affect your vehicle's warranty depending on the terms and conditions of your specific warranty agreement. We recommend checking with your warranty provider before proceeding with the conversion.

Should you encounter any problems post-conversion, we recommend contacting your conversion specialist for troubleshooting advice or potential service needs.

Yes, an Allison transmission from another vehicle can be used, provided it's compatible with your Ford model. Ensure to consult with your conversion specialist before proceeding.

Yes, we provide rebuilding services for Allison transmissions, ensuring your transmission operates at peak performance.

The cost can vary significantly depending on the specific Allison model, whether you're providing the transmission or purchasing it as part of the kit, and any additional services required. Please contact us directly for a more accurate estimate.

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