The Batmobile (now also called, The Fatmobile), 2004 BMW 645Ci, started getting SMG transmission problems 4-5 years ago, first symptoms came during the fall of 2018. The project is still going, but seems that we have solved the original issue, but because the issue was for such a long time we now have to repair things around it AGAIN, which have been repaired many times before. Good thing is that with the help of Pro Hooldus in Tallinn now know what originally was causing all the problems.


Start with the list of what have been done, and with red color what helped with the original problem.

– SMG transmission adaptation (February 2019)
– hydraulic fluid level check (February 2019)
– Sammon colored relay (February 2019)
– Battery (May 2019)
– All fuses checked (May 2019)
– Wires (June 2019)
– Clutch (September 2019)
– Wheelbearings to the driveshaft (September 2019)
– Driveshaft wheelbearings second time (September 2019)
– Hydraulic pump (September 2019)

Covid border lockdown, waited many months.

– Hydraulic pump, second time a new pump (June 2020)
– Changed the the sammon/orange relay (January 2022)
– Changed the hydraulic pump (January 2022)
– Repaired the slave cylinder / clutch actuator (January 2022)
– Cleaned 4 solenoids of the smg hydraulic system (January 2022)
– Ecu box repair, one pin was borken in the connection (Summer 2022)
– Ecu box cloning, failed 2 times, (Summer 2022)
– Ecu box cloned, success, (Fall 2022)
-3 solenoids (March 2023)
-Shift actuator (March 2023)

SMG Valve Block (March 2023)


And the whole story

For the last 4 years things that have been done are the following, in order that they have been done and this things have been done because “professionals” and “specialists” have claimed that these are the problems, we start with the first diagnoses and reapairs around exactly 4 years ago (spring of 2019).

The first place, February 2019 (one hour):
– SMG transmission adaptation
– hydraulic fluid level check

After first symptoms I drove to place where they plugged in their computer, ran the adaptation of the smg transmission, which went through without problems. They checked the hydraulic oil level and it was ok, so they did not find anything.

Fix by myself, February 2019:

Two days later the symptoms became bad and the car went into fault mode and I could not start the car anymore. First I changed the famous sammon color relay and reset all errors with attached computer with help of a friend of mine (at that time I did not know that it wouldn’t help because about 99% of info on the internet is stating, the relay is the problem).

It did not help or change anything so my friend suggested a small repair shop who does special cars, even Ferraris. Well I have my doubts about the Ferraris and special cars after my experience with the place. And this place was so claimed to be so good that his waiting line for cars was 2 months and more. So after a two months of waiting the car was towed to this place.

The second place, April 2019 – May 2019 (1 month):
– Battery
– Fuses checked

Which did not help anything, still same problem and car not running and not driveable. So we went and towed the car back home. On top of everything they had somehow managed to get the BMW emblem off the key, so still today one of my keys is lacking the BMW emblem (which of course the place denied that they did). And all this took 1 month, to change a battery can check the fuses. So the car was towed back home.

A week later I hear about a place (the third place) that said on the phone that this was a simple job, so I tow the car to them.

Third place, May 2019 – June 2019 (1 month):
– Wires
They said they got the car running after the shaked/pushed the electric wires of the smg transmission, and they said that changing the wires to new, would help, but they also said they can’t say for sure that it will help. So I said ok, change the wires. They did and nothing changed. They then clamied only thing that I can do is change the whole transmission, not only the hydraulic system, but the whole transmission. They clamied official BMW Finland also said the same. I disagreed and went and towed the car back home again.

Fourth place, July 2019 – September 2019 (2 months):
Then I heard about a place in Tallinn that is good with transmissions, so we towed the car to this place. It took them many months to even do anything or diagonse anything, the car had been sitting there even if they said they will start working on it right away, and finally in September 2019, YES it took them 2 months to even look at the car and what they finally did was:
– Clutch
– Wheelbearings to the driveshaft

– The airconditioner kompressor (because they said it was old and worn out, but they never asked me for if it is ok that they change it)

They had got it to work, and I drove home. It was fall / winter time so it never heated up so no symptoms, but I heard a rattling sound, so I took the car back.

Fourth place, second time, September 2019 (1 month):
The wheelbearing for the driveshaft that they changed was faulty so they changed it again.
After I picked up the car a couple of hours later and drove off and stopped for a pizza and after eating when started the car I got the orange/yellow clog wheel error on the dashboard and I was able to limp back to the place.
I can’t remember exactly what they did to the car, but got the errors cleared and said I can drive home. But when I tried to drive away the second time the car (smg transmission) died while driving out their gate. So they helped me push the car back and I left home again without the car.
After waiting for 1 month they told me the car is repaired and that the hydraulic pump had failed.
– Driveshaft wheelbearings (second time, first new one was faulty so changed a new one covered by warranty)
– Hydraulic pump


At this point, I really believed the problem was gone, because so far they had changed the clucth and the hydraulic pump in the SMG transmission. This was end of November when I got the car back home and happily drove around thinking everything was ok.

3 months later I the symptoms game back, what I now know that I didn’t know back then was that the symptoms did not appear during December and January, until later February, because the SMG transmission never got so hot during those cold months in Finland.

The symptoms were the same as before but with a wierd difference with the gears.
The change of the hydraulic pump and the clutch somehow (which is still a mystery today) made this wierd thing happened with the symptoms. Earlier it was gears 2, 4 and 6 that did not work when the SMG hydraulic oil got hot and now these gears worked ok and instead 1, 3, 5 and R did not work.
These symptoms started in February 2020. I had not noticed the symptoms earlier because I mainly drove another car and the BMW 645 stayed in the garage for most of the time and was drive only very short drives in cold weather. Also at the same time covid had locked down borders so I had to wait a couple of months before I could take the car back to Tallinn.

Fourth place, third time, June 2020 (2 weeks):
– Hydraulic pump (second time a new pump)
They promised that they would start working on the car right away but they waited for almost 2 weeks to start working on it, and they started working on it only when I contacted them again.
They changed the hydraulic pump again, and claimed this was the reason to the transmission problems.
I drove home and everything seemed to work. So, so far we have a new clutch and a new hydraulic pump. Everything seemed to work and I was happy.

I was driving for about a year without and big issues, only issue I got that a couple of times it took a long time before it engaged a gear from neutral to first gear or reverse after I use the gear lever. And once after a fast acceleration from stand still, something was dripping out of the system, just small drips (now later, i suspect it was from the smg hydraulic system, as I later got to learn it was leaking).

Then the same symptoms as before when getting hot during fall of 2021. Then January 2022 while driving it didn’t want to put second third gear from second, so I stopped to the side of the road and got it into neutral, and after that it had no response when trying to change gear with the gear lever.

Fifth place, January 2022:
– Changed the the sammon/orange relay
It did not help, so we towed the car to the fifth place

Sixth place, January 2022:
– Changed the hydraulic pump
– Repaired the slave cylinder / clutch actuator (not properly repaired)
– Cleaned 4 solenoids of the smg hydraulic system

The hydraulic pump was broken, because of leaks in the systems. Also the hydraulic fluid container was broken, it had been tightened to much and it was broken. And just in case they cleaned all the solenoids. They also repaired the clutch actuator, which I now know that the repair was not properly made.

These to this was supposed to do the trick, but no, still the same symptoms. So I took it back to the place. And the next thing was that they thought it might be a computer issue. And yes, the car had an ecu problem, a connector/pin was bent, almost broken. The place was to take it to a super place, the place I trust for electronics.

Sixth place, many more times, Summer of 2022:
– Ecu box cloning (failed 2 times, two used ecu boxes, either the cloning attempts messed them up or they did not work from the beginning)

Seventh place, Summer of 2022
This place cloned the Ecu for me. They did what they say they would, this place knows electronics. Super place.
– Ecu box cloned (success)

Eight place, Pro Hooldus, December 2022 (4 months, but rebuilt the whole engine at the same time)
-3 solenoids
-Shift actuator

We changed the solenoids.
Then we changed the Shift actuator.
Now waiting to change the valve block.
-SMG valve block
The work started in December and the reason why it has taken so long is that we rebuilt the whole engine at the same time, so that is why we did not start testing until now in March 2023.
We first changed 3 of the solenoids, did not help. We then decided to change the valve block.

After changing the SMG valve block everything started working. One day testing and even when the car was hot (SMG transmission fluid also hot) it still worked fine. Next day some driving and ok. Then car went into transmission error mode, meaning 1, 2, 3 and R gears usable. While limping back to the garage it took a lot of time for the gears to engange. Diagonstics said low hydraulic pressure and when we got the car up, hydraulic fluid container was empty. Filled it up, did the adaptation and it worked. BUT there is a wierd sound when changing gears. So our assumtion now is that:
A. Clutch actuator is leaking (that was supposed to be repaired properly about a year ago by the sixth place)
B. The shift actuator that we changed is leaking.
C. Both A and B

Also what I now know, is that the SMG transmission has worked for a while with the pump going overkill all the time and that way it has been able to compansate the valve block not properly working (I can’t state this for a fact, just a speculation).

TO BE CONTINUED…

Quick update, it was A, the Clutch actuator is leaking. So now we know the problem for the leak and we will be able to repair it. Next step to get a repaired clutch actuator from SMG Society. SMG Society is really one of the best if not best place for SMG knowledge and parts.