(BMW 645 SMG) Transmission Problems/Repair Costs/Fluid Change

Last Updated on September 25, 2023 by Robert Wilson

BMW 645 SMG Transmission Problems have been occurring since the car was first released in 2003.

The problem seems to be with the software that controls the transmission, and it is unclear why BMW has not been able to fix the issue.

Some owners have reported that their car will suddenly lurch forward or backward when stopped, while others say that their transmission will slip out of gear while driving.

Many owners have had to take their car to the dealer for repairs, but the problem often persists.

BMW 645 SMG Transmission Problems: The BMW 645 is a great car, but it seems that many owners are having problems with the SMG transmission.

There have been reports of the transmission slipping, grinding gears, and even failing altogether.

BMW has issued a recall for the affected vehicles, but many owners are still out of luck.

If you own a 645 with an SMG transmission, be sure to keep an eye on it and take it to your dealer if you notice any problems.

In the meantime, we hope that BMW can figure out what’s causing these issues and get them fixed soon.


Do You Have to Shift a SMG Transmission?

Yes, you have to shift a SMG transmission. The reason is because the clutch is operated by an electro-hydraulic system and there are no physical clutch or gearshift levers for the driver to operate. Instead, all shifting is done via paddles located on the steering wheel.

How Do You Use the Transmission on a BMW SMG?

If you’re lucky enough to have a BMW with an SMG transmission, you know that it’s a unique and exhilarating experience.

Here’s a quick guide on how to use it:

To engage the SMG transmission, simply press the gear shift lever to the left and then forward.

You’ll feel and hear a slight click as it engages. To disengage, simply press the lever back to the Neutral position. The beauty of an SMG transmission is that it offers both automatic and manual shifting modes.

In Automatic mode, simply put the shifter in Drive (D) and let the car do all the work. It will upshift and downshift based on your speed and throttle input.

If you want more control, select Manual mode by moving the shifter into M/S position.

Now you’ll be able to use paddle shifters behind the steering wheel to upshift and downshift just like a Formula 1 driver!

Just blip the throttle when shifting gears for best results. Have fun exploring all that your BMW’s SMG transmission has to offer!

Is the E46 M3 SMG Reliable?

The M3 SMG is a 6 speed sequential manual gearbox manufactured by Getrag for BMW. It was used in the E46 M3 from 2001-2006.

The SMG uses an electronically controlled clutch and gearbox to provide extremely fast gear changes with no interruption in power delivery.

It also has a launch control feature and a “power” mode which makes the car more responsive.

However, many people have experienced problems with the SMG, particularly with the early versions of the gearbox. Common issues include jerky shifts, erratic behavior, and difficulty selecting gears.

These problems can be exacerbated by hot weather or hard driving. BMW has released several software updates over the years to try and improve the reliability of the SMG, but it still remains a controversial topic among M3 owners.

What Does BMW SMG Stand For?

BMW SMG stands for “Sequential M gearbox”. This type of transmission was first used by BMW in the 1988 E36 M3.

The main advantages of an SMG over a traditional manual transmission are quicker shift times and the ability to “pre-select” gears.

In other words, an SMG can upshift or downshift without the driver having to use the clutch pedal.

The SMG system uses an electrohydraulic actuator to control the clutch and shifting mechanism. There is also a computer that monitors engine speed, throttle position, and braking pressure.

When the driver wants to shift gears, they simply push a button on the steering wheel or move the shifter lever into the desired position.

The computer then does all of the work needed to make the shift happen smoothly and quickly. Since it was first introduced, BMW has continued to refine the SMG system.

The latest version is called “M DCT” (double clutch transmission) and is used in some of their high-performance cars such as the M5 and M6.

Bmw 645 Smg Transmission Problems

2005 Bmw 645Ci

The 2005 BMW 645Ci is a high performance luxury car that was produced by the German automaker BMW.

It was based on the E63 platform, which was also used for the 5 Series and 7 Series cars. The 645Ci was available in both coupe and convertible body styles, and it came equipped with a 4.4-liter V8 engine that produced 360 horsepower.

It had a top speed of 155 mph and could accelerate from 0-60 mph in just 5 seconds. The 645Ci featured many luxury amenities, such as heated front seats, navigation system, premium sound system, and rain-sensing windshield wipers.

It also had a number of safety features, including front and rear airbags, ABS brakes, traction control, and stability control.

Most Common BMW 645 SMG Transmission Issues

  1. Lack of Response
  2. Leaking Fluid
  3. Low Fluid
  4. Burning Smell
  5. Grinding or Shaking
  6. Gears Slipping

(Bmw 645 Smg) Transmission Fluid Change (Video)

(Bmw 645 Smg) Transmission OIL Change (Video)


If you’re the owner of a BMW 645 with an SMG transmission, you may be having some problems.

The good news is that there are some things you can do to help fix the issues. First, make sure that your transmission fluid is at the correct level and that it’s clean.

You should also check the transmission filter to see if it needs to be replaced. If you’re still having problems, you may need to have your transmission serviced by a professional.


  • Robert Wilson

    Introducing Robert Wilson, your go-to source for automotive technical solutions. With 5 years of industry experience and a mechanical engineering background, Robert's expertise was honed at the heart of Ford Motors in Michigan back in 2010. Join him on this blog as he shares his knowledge and practical fixes to keep your vehicles running at their best.

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