BMW M3 F80 M4 F82 DKG gearbox complete

For the BMW F80 M3 and F82 M4, the 7-speed M-DCT (Double-Clutch Transmission), internally known as the GS7D36SG, is one of the most robust and high-performing gearboxes ever fitted to a production BMW.

If you are looking for a “complete” unit—whether for a replacement, a manual-to-DKG conversion, or a high-power build—here are the essential technical details.

1. Transmission Specifications (GS7D36SG)

The F8x DKG was specifically engineered to handle the high-torque delivery of the S55 twin-turbo engine. It differs significantly from the older E92 M3 units (GS7D36BG) in its gear ratios and torque capacity.

• Torque Rating: Rated for ~700 Nm (516 lb-ft) from the factory, but widely known in the tuning community to hold up to 900 Nm on stock clutches with a proper TCU (Transmission Control Unit) flash.

• Gear Ratios: * 5th Gear: 1.00:1 (Direct Drive)

  • 7th Gear: 0.67:1 (Overdrive for fuel efficiency)

• Weight: Approximately 77 kg (170 lbs), which is significantly lighter than traditional torque-converter automatics while maintaining high structural rigidity.

2. What defines a “Complete” Assembly?

In the secondary market or for factory orders, a “complete” gearbox should include the following five core components to be considered “ready-to-run”:

1. Main Transmission Housing: The GS7D36SG case with internal gear sets.

2. Dual-Clutch Pack: The internal wet-clutch assembly (comprising a small and large clutch basket).

   Mechatronics Unit: The “brain” of the transmission, containing the solenoids, valves, and the TCU.

3. Oil Pan & Internal Filters: The plastic (or upgraded aluminum) pan and the internal suction/pressure filters.

4. Output Flange: The connection point for the Carbon Fiber (Pre-2018) or Steel (Post-2018) driveshaft.

3. Key Upgrades for High-Power Builds

If you are sourcing a gearbox for a car making over 600 WHP, enthusiasts often look for “complete” packages that already include these common upgrades:

• Billet Aluminum Oil Pan: Replaces the leak-prone OEM plastic pan and adds ~1.5L of fluid capacity for better cooling.

• Upgraded Clutch Packs: (e.g., Dodson or DEKA) These increase the friction surface area, allowing the transmission to hold 1,000+ Nm of torque.

• GTS/CS Transmission Flash: A software update that increases clutch clamping pressure and provides faster, crisper shifts compared to the standard “Base” or “Competition” software.

Comparison: Early vs. Late Model Units

Note on Compatibility: While the transmission itself is physically the same across all years, the output flange changed in 2018 when BMW switched from carbon to steel driveshafts. If you buy a “complete” unit from a 2015 car for a 2019 car, you may need to swap your existing flange.