The B&M Megashifter and Shift Plus+ Electronic Shift Improver are widely used by DIY enthusiasts and performance vehicle owners to enhance the driving experience in GM vehicles equipped with the 4L60E or 4L80E automatic transmissions. These products offer improved shift firmness and responsiveness, making them popular upgrades for those looking to optimize their vehicle's performance. This article provides a detailed, step-by-step guide to installing the B&M Megashifter and Shift Plus+ Electronic Shift Improver, drawing exclusively from the technical details and user experiences outlined in the source materials.
Overview of B&M Megashifter and Shift Plus+
The B&M Megashifter is a ratchet-style shifter designed to replace the stock shifter in GM vehicles with 4L60E and 4L80E transmissions. It provides a more direct and precise shifting action, reducing shift throw and improving gear engagement. The Shift Plus+ Electronic Shift Improver complements the mechanical upgrade by electronically enhancing the shift characteristics of the transmission. Together, these components are engineered to provide a more responsive and aggressive driving experience.
The installation process involves removing the stock shifter and console, preparing the B&M Megashifter for mounting, and integrating the Shift Plus+ unit into the vehicle's powertrain control system. While the procedures are relatively straightforward, they require careful attention to detail to ensure proper fit and function.
Tools and Materials Required
Before beginning the installation, it is essential to gather the necessary tools and materials. These include:
- Basic hand tools: Phillips and flathead screwdrivers, socket and wrench set (including 10mm and 7mm sizes), pliers, and a vise.
- Cutting and shaping tools: Dremel with steel-reinforced cutting bit, angle grinder with cutting disk, and a welder (optional for customization).
- Electrical tools: Wire cutters, wire crimpers, and a multimeter (optional for testing).
- Installation-specific components:
- B&M Megashifter (part numbers 80690 or 80694)
- B&M Shift Plus+ Electronic Shift Improver
- B&M Neutral Switch (or equivalent, such as Radio Shack 275-017 roller switch)
- B&M T-Handle with Button (part number 4440)
- 3/8" threaded rod (for mounting modifications)
- Countersink screws for mounting the shifter bezel
Additional materials may be required depending on the specific modifications made to the shifter or console. It is recommended to review the manufacturer’s installation instructions and user experiences to anticipate any unique requirements for the specific vehicle model.
Step-by-Step Installation Guide
1. Disconnect the Negative Battery Cable
Before beginning any electrical or mechanical work, it is crucial to disconnect the negative battery cable. This step ensures safety by preventing accidental activation of electrical systems during the installation process.
2. Remove the Upper Console
The upper console must be removed to access the stock shifter and its mounting points. Begin by removing the two Phillips screws located under the coin holder. Once these are removed, the console can be lifted and pulled upward to clear the area around the shifter. Care should be taken to avoid damaging the surrounding trim, especially in the area near the emergency brake handle.
3. Remove the Lower Console
The lower section of the console is secured by two 10mm nuts located at the bottom of the compartment and two 7mm screws near the front, beneath the air conditioning controls. These must be removed to gain access to the wiring and linkage connected to the stock shifter. Additionally, the wiring harness for the power plug must be disconnected. The release mechanism for the harness is located at the bottom of the connector, which may require some effort to depress and disconnect.
4. Remove the Stock Shifter, Linkage, and Wiring
The stock shifter is bolted into place using two 10mm nuts and two 10mm bolts. These must be removed to free the shifter from its mounting. A small screwdriver is useful for disengaging the linkage from the shifter. Once the nuts and bolts are removed, the stock shifter can be lifted out, along with its associated linkage and wiring.
Some of the components, such as the neutral safety switch and the brake override linkage, can remain in place but should be disconnected and set aside for later reference. It is important to note the orientation and positioning of these components to ensure proper reinstallation or modification during the B&M Megashifter installation.
5. Modify and Prepare the B&M Megashifter
The B&M Megashifter may require modifications to fit properly into the vehicle’s console and to accommodate the stock linkage. One common modification involves extending the shifter body using a 3/8" threaded rod. This allows the shifter to be mounted securely without flexing or loosening over time. Some users have opted to weld the extension in place, while others use nuts and bolts for a more adjustable setup.
Additionally, the shifter may need to be adjusted horizontally or vertically to ensure proper clearance with the console and surrounding components. In some cases, users have had to trim the console subframe or the shifter plate to achieve the necessary clearance. These adjustments are typically minor and can be accomplished with a Dremel or angle grinder.
6. Mount the B&M Megashifter
Once the shifter has been modified, it can be mounted into the console. The upper mounting points of the console can be used to secure the shifter bezel, typically using 1" long countersink screws. It is important to ensure that the shifter is mounted securely and aligned with the transmission linkage. Some users have reported that the shifter should be positioned slightly to the right to avoid interference with the gear selector plate and light assembly.
After the shifter is mounted, the stock linkage can be reconnected to the transmission. The linkage should be adjusted to ensure smooth and precise shifting. It is also important to verify that the shifter is properly aligned with the gear positions and that the T-handle functions correctly.
7. Install the Shift Plus+ Electronic Shift Improver
The Shift Plus+ Electronic Shift Improver is installed by connecting it to the Powertrain Control Module (PCM) of the vehicle. The PCM is typically located under the hood or under the dashboard. Once located, the wire loom should be carefully removed to allow access to the wiring harness.
The Shift Plus+ unit must be connected to the appropriate wires in the PCM harness. The installation instructions provided by B&M should be followed carefully to ensure the correct wiring connections. Once the wiring is completed, the Shift Plus+ can be mounted in a convenient location, such as under the dashboard or behind the console.
8. Reassemble the Console
After the shifter and Shift Plus+ unit are installed, the console can be reassembled. The upper and lower sections of the console should be reattached using the original screws and hardware. Care should be taken to ensure that all wiring and components are properly secured and that the console fits snugly without gaps or misalignment.
Once the console is reassembled, the ignition should be turned on to test the functionality of the new shifter and Shift Plus+ system. The shifter should be tested in all gear positions to ensure smooth and consistent operation. The Shift Plus+ can be toggled between different modes to verify that the shift characteristics are improved as expected.
Additional Considerations and Tips
Transmission Cooling: The source materials mention the importance of maintaining proper transmission temperature, especially in high-performance or towing applications. B&M recommends the use of their SuperCooler Automatic Transmission Cooler to prevent overheating and transmission failure. This is particularly relevant for vehicles used in heavy-duty applications such as racing, towing, or frequent high-speed driving.
Fluid Recommendations: To complement the mechanical and electronic upgrades, B&M recommends using their Trick Shift Performance Automatic Transmission Fluid (ATF). This specially blended fluid is designed to provide enhanced protection and faster shift response. It is recommended to replace the existing transmission fluid with the B&M Trick Shift fluid after installation to maximize the benefits of the upgrade.
User Modifications: Some users have opted to replace the standard B&M neutral switch with a Radio Shack roller switch due to availability. While this is a viable alternative, it is important to ensure that the switch is compatible with the vehicle’s wiring and that it functions correctly. The neutral safety switch is critical for preventing the vehicle from starting in gear, so it should be tested thoroughly after installation.
Console Modifications: As noted in the user experiences, some minor modifications to the console may be necessary to accommodate the B&M Megashifter. These can include trimming the console subframe, adjusting the shifter position, or modifying the shifter plate for clearance. These changes are typically minimal and can be performed with basic hand tools.
Testing and Troubleshooting: After installation, it is essential to test the shifter and Shift Plus+ system in a safe environment. This includes verifying that all gears engage properly, that the neutral safety switch functions correctly, and that the Shift Plus+ is operating as intended. If any issues are encountered, the wiring connections should be checked, and the installation steps should be reviewed for potential errors.
Conclusion
The B&M Megashifter and Shift Plus+ Electronic Shift Improver are valuable upgrades for GM vehicles equipped with the 4L60E or 4L80E transmissions. These components offer improved shift firmness, responsiveness, and overall driving experience. The installation process, while requiring some mechanical skill, is generally manageable for DIY enthusiasts with basic tools and knowledge.
By following the step-by-step guide outlined in this article and using the tools and materials recommended by B&M and user experiences, the installation can be completed successfully. Additionally, considering supplementary recommendations such as transmission cooling and fluid upgrades can further enhance the performance and longevity of the vehicle's drivetrain.