6-Speed Manual Conversion for S85

We’ve all been there. You’re ready to take off at the red light, you lift your foot off the brake, press the gas—and then… nothing. "DING"

A red cog! THE red cog of death for these cars. Almost as bad as having your rod bearings let go mid-pull on a spirited drive.

Don’t get me wrong—there’s absolutely no issue with the 7-speed automatic in terms of driving experience and gear-snapping excitement. The SMG 3 (Sequential Manual Gearbox) was a major part of the M5’s initial launch in 2005, and even today, it still holds its place inside these engineering marvels.

But the downside? Reliability issues start creeping in when these cars move into their second or third ownership. Rebuilding internals, rewiring harnesses, and replacing worn components become inevitable if you're chasing long-term durability.

While BMW’s goal was to deliver the best of both worlds—manual-like performance with automated control—the long-term viability of SMG 3 hasn’t aged as gracefully. Especially not for owners who push their S85s hard or plan to keep them for the long haul.

BMW revolutionized the driving experience by pushing the boundaries of automated shifting, offering an exhilarating drive with the SMG 3. However, as time went on, reliability concerns began to surface, making it clear that there were trade-offs. So, what can you do if your SMG 3 is starting to show its age?

Rebuilding the SMG 3: A Viable Option

The 6-Speed Manual Conversion: A Light at the End of the Tunnel

Alternatively, there is a light at the end of the tunnel—a true escape from the complexities and potential headaches of an SMG rebuild. Imagine yourself fully in control of your German V10 sedan, rowing through the gears with that raw, mechanical connection between you and the engine. This is the ultimate driving experience.

And while the SMG 3 may have been groundbreaking in its time, for many drivers, the pure joy of a 6-speed manual is unmatched. This is where we come in. We specialize in both repairing the SMG 3 and converting your car to a 6-speed manual giving you the flexibility to choose the option that best suits your driving desires.

For those who prefer to rebuild their SMG 3, we provide expert services that adhere strictly to BMW’s factory standards, ensuring your transmission is as reliable as the day it was first installed. But if the manual experience calls to you, we can also help convert your car to a full 6-speed manual transmission, delivering that classic, tactile driving experience that only a manual can offer.

Our priority is the long-term performance of your vehicle. Whether you choose to repair or convert, we ensure that every step is completed with the same precision and care that BMW put into these machines when they first rolled off the production line.

The 6-Speed Manual Conversion: Your Journey Starts Now

Our journey to convert the M5 E60 from an automated manual transmission (SMG) to a fully functional 6-speed manual transmission starts now. When these cars were first sold, BMW gave first owners the rare option to spec their M5 or M6 with a stick. Allegedly, only about 1 in 10 owners took that path.

While most cars came equipped with the SMG system, every E60, E61, E63, and E64 chassis was designed to accommodate the 6-speed manual. The transmission used for this swap is the GS6-53BZ-TJGC, originally found in the manual S65-powered M3 models (E90 and E92).

This transmission is almost identical to the one that came in the M5 and M6—the GS6-53BZ-THGR—but minor adjustments are required to ensure proper fit and function with the S85 engine.

While the THGR transmission housing is the same and shares the same mounting bolt pattern, there are key differences in transmission mounts, bell housing fitment, clutch, slave cylinder, and removal of the transmission oil cooler.

The 6-Speed Manual Swap: S85 Side

The process begins by carefully removing the existing transmission and related components to make room for the new setup. This involves disconnecting and removing the exhaust system, driveshaft, flywheel, and the Transmission Control Unit (TCU).

With the car disassembled, we use this opportunity to perform critical preventive maintenance. If the following components are still original, this is the best time to replace them to avoid future failures:

• Crankcase Breather Hose – ••••••••••• OE Part Number
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• Crankcase Breather Hose – ••••••••••• OE Part Number
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• Crankcase Vent Valve – ••••••••••• OE Part Number
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• Rear Main Seal – ••••••••••• OE Part Number
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• Exhaust Gaskets & Bushings – (Inspected on removal) – Qty: As needed

A key area is the rear subframe bushings. These wear over time and can crack—especially problematic when converting to a manual transmission. Hard launches with worn bushings can damage the subframe’s differential mounting tabs.

BMW has since updated these bushings with improved versions. Replacing them and reinforcing the subframe is recommended if wear or damage is present.

For more on reinforcement and servicing the driveline, visit our BMW Service: Rear Drive Train Service for S85 page: [link coming soon].

Clutch Control

Pedal Assembly

Other Parts

Shift Knob & Accessories

Shifter Carrier

Clutch Components

Gearbox Mounting

Gearbox Housing (Not Required)

The 6-Speed Manual Swap: Interior Modifications (Not Required)

When converting your BMW M5 or M6 from the SMG transmission to a 6-speed manual, the process involves more than replacing the gearbox. The interior can also be updated to properly accommodate the manual shifter and related components. Although these changes are not mechanically required, they allow the vehicle to retain its functional features with a clean OEM-style appearance.

Center Console Trim

On PRE-LCI vehicles, the original SMG center console layout differs from the manual configuration. The manual conversion uses a dedicated fixed oddments tray that provides the correct storage area and mounting location for the EDC button.

The PRE-LCI manual oddments tray replaces the original retractable ashtray assembly. It retains the lighter outlet, provides the correct opening for the EDC button and removes the front ashtray from the center console. This original Genuine BMW manual tray has been discontinued.

• PRE-LCI Manual M5 E6X Oddments Tray – ••••••••••• OE Part Number
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  Includes EDC Button – ••••••••••• OE Part Number
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  Discontinued

On LCI vehicles, the decor panel is shared between SMG and manual configurations within the corresponding CCC or CIC setup. The LCI CCC decor panel, part number 51168037228, is supplied with a plain storage cubby that does not have an opening for the EDC button. The LCI CIC decor panel, part number 51167903535, is supplied as the decor panel only and does not include a tray or EDC button. To complete the factory-style manual layout, the Genuine GEMS manual oddments tray and the EDC button are installed separately.

• LCI CCC M5 E6X Decor Panel With Storage Cubby – SMG or Manual – ••••••••••• OE Part Number
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  Includes a plain storage cubby. The cubby does not include an EDC-button opening or an EDC button.
• LCI CIC M5 E6X Decor Panel Alu Shadow – SMG or Manual – ••••••••••• OE Part Number
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  Decor panel only. Does not include an oddments tray or EDC button.
• BMW Manual Swap Center Console Oddments Tray - Genuine GEMS – 51168045434 – Qty: 1
  EDC Button sold separately – ••••••••••• OE Part Number
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Additional Components Required for LCI CIC Conversion

When converting to the LCI CIC configuration, the updated iDrive controller requires specific mounting components to fit correctly. The required parts are listed below:

• LCI iDrive Telematics Input Controller – ••••••••••• OE Part Number
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  Includes Trim Ring – ••••••••••• OE Part Number
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• iDrive Controller Mount Frame – ••••••••••• OE Part Number
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• iDrive Controller Support – ••••••••••• OE Part Number
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• Controller Trim Ring (Pearl Grey) – ••••••••••• OE Part Number
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  Can be replaced separately if a used controller is sourced with a damaged ring

No replacement is required if the original EDC button is still in good condition. Reuse the EDC button from the existing SMG III shifter surround trim.

• M5/M6 E6X EDC Button – ••••••••••• OE Part Number
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  Reuse the EDC button from the existing SMG III trim

Steering Wheel

As part of the manual transmission conversion...

BMW offered two steering wheel options for manual M vehicles...

• 1. Manual M5/M6 E6X Steering Wheel (Non-Heated) — ••••••••••• OE Part Number
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• 2. Manual M5/M6 E6X Steering Wheel (Heated) — ••••••••••• OE Part Number
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If your current steering wheel lacks heating but you would like to add this feature...

For more details, visit our BMW Service: Heated Steering Retrofit for S85 page: [Link coming soon].

Completed

At this stage of the manual conversion, the manual transmission and essential functions are fully operational.