BMW SMG III explained: how the M5 E60 gearbox works

The BMW SMG III is the seven-speed sequential gearbox of the M5 E60 and the M6 E63/E64. It is often misunderstood: it is not an automatic and not a dual-clutch gearbox, but a manual gearbox with a single clutch that is operated by hydraulics and a computer.

In this article we explain how SMG III works, what Drivelogic and launch control do, which parts wear and how to drive it smoothly in everyday traffic.

What BMW SMG III is

SMG stands for Sequential M Gearbox. BMW M first offered it on the E36 M3 in the late 1990s, followed by the SMG II on the E46 M3 and the M3 CSL. The third generation, SMG III, arrived in 2005 with the V10-powered M5 E60 and was also used in the M6.

The idea comes from motorsport. A conventional manual gearbox gives a direct connection between engine and wheels, but the driver has to work the clutch and the gear lever. SMG keeps the manual gearbox and the single dry clutch, but replaces the driver's left foot and right hand with an electro-hydraulic system.

The driver chooses gears with paddles on the steering wheel or with the short selector lever on the centre console. The computer then opens the clutch, changes gear and closes the clutch again, faster and more precisely than most people could do it themselves. In automatic mode, it also decides when to shift.

The result is a gearbox that feels very direct and mechanical, with the sound and character of a manual, but with the speed of a racing gearbox. That is also why it behaves differently from a modern torque converter automatic or a dual-clutch gearbox.

How it works inside

Inside the SMG III there is a seven-speed manual gearbox built by Getrag, connected to the V10 through a twin-plate dry clutch. The difference from a normal manual gearbox is the actuator system on the outside.

A hydraulic unit with an electric pump keeps a pressure accumulator charged with hydraulic fluid. When the driver asks for a gear change, valves send this pressure to two actuators: one moves the clutch and one moves the gear selection mechanism. A dedicated control unit coordinates everything with the engine management, which briefly reduces engine torque during the shift.

Sensors tell the computer the exact position of the clutch and the gears, the engine speed and the road speed. Because all of this happens in fractions of a second, upshifts at full throttle feel like a firm push in the back.

The system needs the hydraulic pressure to work. That is why you can sometimes hear the pump run briefly when you open the driver's door or start the car: it is preparing the system so that the first gear can be selected immediately.

Drivelogic: eleven shift programs

SMG III gives the driver a choice of eleven shift programs, called Drivelogic. There are five programs in the automatic mode (D) and six in the sequential manual mode (S). The driver selects them with a button next to the gear lever.

In D mode, program 1 shifts very smoothly and early, which is ideal for slow traffic, while the higher programs shift later and faster. In S mode, the driver changes gears with the paddles or the lever, and the program decides how fast and how firm the shifts are. S1 is soft and comfortable; S6 gives the quickest and most aggressive shifts.

Most owners find a comfortable setting for daily use in the middle of the range and keep the fastest programs for open roads or the track. The faster programs put more load on the clutch and the drivetrain, so they are not the best choice in city traffic.

Drivelogic is combined with the other settings of the M5, such as the power mode, the EDC damper settings and the DSC stability control, which can all be stored on the M button on the steering wheel.

Launch control

The M5 E60 was one of the first saloon cars with a launch control function. It is available in the sequential mode with the fastest shift program and with DSC switched off.

When it is activated, the driver holds the selector lever forward, presses the accelerator fully and the engine holds an optimal speed. When the lever is released, the clutch closes and the system manages wheel slip and the shift points for a maximum acceleration start.

Launch control is impressive, but it puts a very high load on the clutch, the gearbox and the rear axle. It is best kept for the track or a closed area, and used rarely. Frequent use will shorten the life of the clutch noticeably.

It is also worth remembering that the M5 is a heavy and powerful car with rear-wheel drive. Even with launch control, starting on a cold or wet surface needs care. On public roads, there is no reason to use it at all.

What wears out and what to check

Like any manual gearbox, the SMG III has a clutch that wears. How fast depends on the driving style: a lot of slow traffic and parking manoeuvres, frequent hill starts and aggressive programs wear it faster. Some clutches last more than 100,000 km, others much less.

The control unit measures the clutch wear, and a specialist with the right diagnostic tool can read the remaining thickness. This is one of the most useful checks before buying an M5 E60.

The other important part is the hydraulic pump. When it starts to fail, gear changes can become slow, the car may show a gearbox warning, or it may refuse to select a gear. Replacement pumps are available, and some problems come from the pump relay or the wiring, which are cheaper to fix.

After a clutch replacement or major work, the system has to be recalibrated with diagnostic equipment, so that the computer knows the new clutch position. A correct calibration also makes shifts smoother in daily driving. Regular hydraulic fluid checks and keeping the battery in good condition help the whole system work properly.

How to drive the SMG III smoothly

Many people who drive an SMG car for the first time find it jerky in automatic mode. The secret is to drive it like a manual gearbox, not like an automatic.

• Lift off the throttle slightly when you shift up with the paddles, just as you would with a clutch pedal. The shift becomes much smoother.
• Use a lower Drivelogic program in traffic and a medium one for normal roads.
• Do not hold the car on a hill with the throttle. Use the brake; holding the car with the clutch heats it up and wears it.
• Select neutral when you wait at long traffic lights, as you would in a manual car.
• Use the sequential mode more often than automatic. Many owners find S mode the most natural way to drive the car.

Driven this way, the SMG III is a rewarding gearbox. The shifts are quick and precise, and the direct connection to the V10 is a big part of what makes the E60 M5 special. US customers could also order a six-speed manual, but in Europe almost every E60 M5 has SMG.

SMG III compared with modern gearboxes

After the E60 generation, BMW M replaced SMG with the seven-speed M dual-clutch transmission (M DCT), first in the E9x M3 in 2008, and later in the F10 M5. A dual-clutch gearbox has two clutches that prepare the next gear in advance, so the power flow is almost uninterrupted and the shifts are smoother in traffic.

Today's M cars mostly use an eight-speed M Steptronic automatic with a torque converter, which is very smooth and strong enough for the high torque of turbocharged engines.

Compared with these gearboxes, SMG III is more raw. The shifts are firmer, and the car needs a more involved driver. That is exactly why many enthusiasts appreciate it today: it belongs to an era of analogue, high-revving M cars.

If you understand how it works and maintain it properly, the SMG III is not a weakness of the E60 M5 but part of its character.

SMG III key facts

Item	Details
Type	Sequential manual gearbox with automated single clutch
Gears	7 forward gears
Clutch	Twin-plate dry clutch, operated hydraulically
Shift programs	11 Drivelogic programs (5 in D, 6 in S)
Launch control	Yes, in S mode with the fastest program and DSC off
Used in	BMW M5 E60/E61 and M6 E63/E64 (2005–2010)
Predecessors	SMG (E36 M3), SMG II (E46 M3 and M3 CSL)
Successor	7-speed M DCT dual-clutch gearbox

Frequently asked questions

Is the BMW SMG III an automatic gearbox?

No. It is a seven-speed manual gearbox with a single clutch. A computer and hydraulics operate the clutch and change the gears, either when the driver uses the paddles or automatically in D mode.

How long does an SMG III clutch last?

It depends strongly on the driving style. Some clutches last more than 100,000 km, others much less, especially with a lot of city driving or frequent launch control starts. A specialist can read the clutch wear with a diagnostic tool.

Why is my SMG gearbox jerky?

Most often because it is driven like an automatic. Lifting off the throttle slightly during upshifts, choosing a suitable Drivelogic program and a correct clutch calibration make the shifts much smoother.

What is the SMG pump?

It is the electric hydraulic pump that keeps the system under pressure so the clutch and the gears can be moved. A failing pump or pump relay can cause slow shifts or gearbox warnings.

Did the BMW M5 E60 have a manual gearbox?

In North America, customers could order a six-speed manual gearbox. In most other markets, the M5 E60 was sold with the seven-speed SMG III.

Sources

• BMW Group PressClub – press material on the BMW M5 (E60) and the SMG III gearbox
• BMW M5 (E60) owner's handbook – SMG III, Drivelogic and launch control
• BMW M – history of the M gearboxes