The B&M Megashifter is a popular upgrade for drivers seeking improved shift feel, reduced shift throw, and enhanced control over automatic transmissions. Designed specifically for 1993–1998 GM vehicles equipped with 4L60E or 4L80E automatic transmissions, the Megashifter provides a more responsive and precise shifting experience. Installation of this device requires a moderate level of mechanical skill and attention to detail, as it involves working with the vehicle’s existing shifter assembly and transmission linkage.
This guide is based on detailed installation experiences shared by users across various forums and installation instructions provided by B&M Racing and Performance Products. It compiles verified steps, tools required, and key considerations from the source material to provide a comprehensive overview for U.S. consumers and DIY enthusiasts.
Overview of the B&M Megashifter
The B&M Megashifter is designed to replace the stock shifter in GM vehicles with 4L60E and 4L80E automatic transmissions. It reduces shift throw by approximately 30–40% compared to the stock shifter, resulting in a more direct and tactile shifting experience. The unit is often paired with the B&M Shift Plus+ Electronic Shift Improver to enhance shift firmness and responsiveness. Together, these components can significantly improve the driving experience in performance-oriented or daily-driven GM models.
The Megashifter includes a redesigned shifter mechanism, a neutral safety switch, and mounting hardware for installation. It is compatible with a wide range of 1993–1998 GM models, including Chevrolet, Pontiac, and Oldsmobile vehicles. Installation requires partial disassembly of the center console and access to the shifter assembly, as well as some modification to the existing linkage system.
Pre-Installation Considerations
Before proceeding with installation, it is important to verify the vehicle’s compatibility and understand the limitations of the B&M Megashifter. The device is intended for use with healthy transmissions and will not improve or correct issues such as worn components, fluid degradation, or PCM-related faults. If the transmission is already experiencing slippage, chatter, or overheating, the Megashifter may exacerbate these problems.
In such cases, it is recommended to address the underlying transmission condition before proceeding with the upgrade. B&M also recommends using their SuperCooler automatic transmission cooler and Trick Shift automatic transmission fluid (ATF) for vehicles used in high-performance or heavy-duty applications. These accessories help manage heat and provide optimal lubrication, which can extend the life of the transmission and improve shift performance.
Tools and Materials Required
Installation of the B&M Megashifter requires a set of standard hand tools and some basic mechanical knowledge. The following tools are commonly used during the installation process:
- Bench vise
- Small flat blade screwdriver
- Long needle nose pliers
- Brake drum adjuster
- 3/8” drive 7/16” socket
- ½” drive 13mm socket
- ½” drive 15mm socket
- 3/8”-drive 10mm socket
- 3/8”-drive 7mm socket
- Side cutters
- Side post terminal wrench
- Cordless 3/8” drive impact driver
- Cordless drill
- ½” drive ratchet
Additional materials may include lithium grease for lubricating bushings and orings, a soft jaw machining vise for holding components during assembly, and a hammer or drift for installing pins and bushings. It is also advisable to have a clean workspace, such as a microfiber towel, to organize parts and prevent loss.
Step-by-Step Installation Instructions
Step 1: Disassemble the Center Console
The first step in installing the B&M Megashifter involves removing the center console to access the shifter assembly. This process requires removing the upper portion of the console, which is typically secured with two Phillips screws. Once these screws are removed, the upper console section can be lifted and pulled away from the vehicle.
The section around the emergency brake handle may be more challenging to remove. Care should be taken to avoid damaging the surrounding trim or plastic components. Users have reported difficulty in this area, and it may be necessary to gently work the section free while supporting it to prevent scratches or cracks.
Next, the lower portion of the console must be removed. This is secured with two 10mm nuts at the bottom of the compartment and two 7mm screws toward the front, located under the air conditioning control panel. In addition, the wiring harness for the power plug in the compartment must be disconnected. The release piece for the harness is typically located at the bottom of the plug and can be difficult to access.
Step 2: Remove the Stock Shifter and Linkage
With the console partially removed, the stock shifter can now be accessed. The shifter is typically secured with two 10mm nuts and two 10mm bolts. These fasteners should be removed carefully to avoid stripping the threads or damaging the surrounding components.
The shifter linkage must also be disconnected. A small screwdriver can be used to release the linkage from the shifter. Once the linkage and fasteners are removed, the stock shifter can be gently pulled out of its mounting location. Users have reported that the shifter may have shims and nylon bushings at the ends, which can fall into the boot during removal. These components should be noted for later installation and reassembly.
A flange bolt may be present at the end of the shift rod adapter. This bolt may be flared on the non-headed end, making it difficult to remove with a standard drift. In such cases, a 9/32” drill bit can be used to clear the flared lip before removing the bolt with a hammer and drift.
Step 3: Assemble the B&M Megashifter
Before installing the B&M Megashifter, it is recommended to assemble the components according to the manufacturer’s diagram. This includes laying out all parts on a clean, flat surface, such as a microfiber towel, to ensure that nothing is misplaced.
Lubrication is an important step during assembly. A small amount of lithium grease should be applied to the grooves of the lower bushing before installing the four orings. These orings should also be coated with lithium grease to ensure smooth operation and prevent wear.
The bushing can then be inserted into the bottom hole of the shifter and allowed to rest in place for now. This will be secured during the final installation phase.
Step 4: Install the Spring Pin and Bushing
One of the key steps in the installation process is the installation of the spring pin between the shifter bushing and the gear shift rod adapter. It is important to ensure the correct orientation of the components during this step.
The lower shift rod should be marked with a ring, and the opening of the ring should be positioned downward when facing the front of the car. The slot in the threads of the shifter should face the rear of the car to ensure proper alignment.
To install the spring pin, the assembly should be held securely in a vise or similar device. The pin can be started into the shift rod, and the slot of the shift rod adapter can be slipped over the lower bushing in the shifter. Once aligned, the pin can be pounded into place with a hammer. A drift can be used to ensure that the pin is recessed equally on both sides.
Step 5: Mount the Shifter and Reconnect Linkage
Once the shifter is assembled and the spring pin is installed, it can be mounted to the vehicle. The B&M Megashifter may require some modification to accommodate the existing linkage system. In some cases, users have extended the shifter using a 3/8” threaded rod for added stability.
The shifter should be bolted into place using the appropriate fasteners. The stock linkage can then be reconnected to the new shifter. It is important to ensure that the linkage is properly aligned and that the shifter moves smoothly through all gear positions.
Step 6: Install the Neutral Safety Switch
The B&M Megashifter includes a neutral safety switch that must be installed to prevent the vehicle from starting in gear. In some cases, users may opt for an alternative switch, such as a Radio Shack 275-017 roller switch, if the B&M switch is unavailable.
The neutral safety switch should be installed according to the manufacturer’s instructions. It is typically mounted near the shifter and connected to the ignition system to ensure proper operation.
Step 7: Reassemble the Console and Test the Shifter
Once the shifter and all components are installed, the center console can be reassembled. The lower section of the console should be resecured with the 10mm nuts and 7mm screws. The upper console can then be replaced and secured with the Phillips screws.
Before completing the installation, the shifter should be tested to ensure that it moves smoothly through all gear positions. The shifter should be moved gently to the 3rd gear position, and the user should listen for any separation or resistance. The nylon bushings and shims should be noted for their orientation and reinstalled as needed.
Troubleshooting and Common Issues
During installation, users may encounter several common issues that can affect the performance of the B&M Megashifter. One of the most frequently reported problems is improper alignment of the shifter and linkage. This can result in difficulty shifting or inconsistent gear engagement. To resolve this, the linkage should be adjusted to ensure that it is properly aligned with the transmission.
Another common issue is the use of worn or damaged components from the stock shifter. These parts can affect the performance of the new shifter and may require replacement. Users should inspect the shifter components for wear and replace any damaged parts before proceeding with the installation.
Some users have also reported difficulty in installing the spring pin due to the orientation of the components. It is important to ensure that the pin is properly aligned and that the shifter and shift rod adapter are correctly positioned before pounding the pin into place.
Maintenance and Care
Once installed, the B&M Megashifter requires minimal maintenance. However, it is important to periodically inspect the components for wear and lubricate the bushings and orings as needed. Lithium grease should be used to ensure smooth operation and prevent corrosion.
If the shifter begins to feel loose or unresponsive, it may be necessary to adjust the linkage or replace the nylon bushings. These bushings can wear over time and may need to be replaced to maintain the precise shift feel.
Users should also monitor the transmission fluid level and condition. The B&M Shift Plus+ Electronic Shift Improver and other performance-oriented components can place additional stress on the transmission, so it is important to use high-quality fluids and maintain proper cooling to prevent overheating.
Conclusion
The B&M Megashifter is a valuable upgrade for drivers seeking improved shift control and responsiveness in 1993–1998 GM vehicles equipped with 4L60E or 4L80E transmissions. While the installation process requires a moderate level of mechanical skill and attention to detail, the results can significantly enhance the driving experience.
By following the step-by-step instructions and using the recommended tools and materials, users can successfully install the Megashifter and enjoy a more precise and tactile shifting experience. However, it is important to ensure that the transmission is in good working condition before proceeding with the upgrade, as the Megashifter is not a solution for existing transmission problems.
With proper installation and maintenance, the B&M Megashifter can provide years of reliable performance and improved driving dynamics for GM enthusiasts and performance-oriented drivers.