Inconsistent SMG Clutch Operation

[oceansize]

This is the advantage of a new slave. There is a one time use “clip” that holds the rod steady as you install so you can be sure this doesn’t happen. On first use it breaks.

[flgman1966]

Okay. Retention clip fished out of transmission. Yeah!!!! Rebuilt Slave cylinder reinstalled. All bleeding completed and fluid at proper level. Transmission Adaption failed. Early. Longitudinal Acceleration Sensor. I have seen a photo of this item on web sites, but can't figure out where it is?? Any one know where the Longitudinal Acceleration Sensor is, appears to be different than the Yaw Sensor.

[eacmen]

Okay. Retention clip fished out of transmission. Yeah!!!! Rebuilt Slave cylinder reinstalled. All bleeding completed and fluid at proper level. Transmission Adaption failed. Early. Longitudinal Acceleration Sensor. I have seen a photo of this item on web sites, but can't figure out where it is?? Any one know where the Longitudinal Acceleration Sensor is, appears to be different than the Yaw Sensor.

Its the expensive one under the drivers carpet. I got a used one off ebay and so far so good.

[eacmen]

This is the advantage of a new slave. There is a one time use “clip” that holds the rod steady as you install so you can be sure this doesn’t happen. On first use it breaks.

Any pro tips for installing a used slave to avoid this from happening?

[flgman1966]

I can tell you that I installed a used Slave Cylinder that I got in eBay, then a rebuilt on from SMG Society in Germany, +-$90. This is only the slave cylinder, not the electrical component. So, I had read somewhere to load the slave cylinder with fluid before installation. I did this to the very top. This is done by depressing the plunger and filling the little connection point with fluid and releasing the plunger to allow it to suck the fluid into the unit. The problem was that during installation as the plunger was depressed it spit fluid out which was frustrating and I then got anxious. I then miss aligned the plunger, completely missing the contact point within the transmission. The first time the unit was activated with pressurized fluid it shot the plunger clean out of the Slave cylinder. This left pieces of the Slave cylinder inside the transmission. Fortunately I was able to fish everything out of the transmission, but wasn't easy. So here is my recommendation:

***This is only for a used or rebuilt unit, not a new unit*** No need to fill the unit with fluid before installation. Although I do think it is a good idea to put some fluid into the unit, Maybe 1 only one depression of the plunger so that there is fluid inside the unit. Then carefully install the unit and feel for the depression of the plunger. If fluid comes out it is normal, but since you don't fill the unit, not much to come out. The fluid line is flexible and so move it out of the way so you don't have to manage it during installation. Tighten all bolts. Attach and tighten the fluid line. Be patient. Not a lot of room. You will only be able to turn fluid bolt a quarter turn at a time. Then use INPA to bleed the Clutch. You will need to fill the reservoir and run the clutch bleed sequence. Again. And again. Check the fluid level. Run it again. Until the bleed sequence completes. It will fail a few times as it fills the fluid line and bleeds out the air. Eventually you will get a successful completion of the Clutch Bleed sequence. Check the fluid level again and adjust.

You will also need to Bleed the Actuator and then conduct a complete Adaption of the Transmission. I would recommend completing all of this before you replace all of the panels on the bottom of the car. Once everything is complete and no leaks, replace panels under the vehicle.

As recall you will need the following for the cylinder:
13 mm socket
Long socket extension. Like maybe 2. I used 1 quarter inch extension an adapter and a half inch extension with a quarter inch socket and half inch socket wrench.
11 mm wrench for fluid line.

I think you will need 8mm socket for the panels.

[eacmen]

I can tell you that I installed a used Slave Cylinder that I got in eBay, then a rebuilt on from SMG Society in Germany, +-$90. This is only the slave cylinder, not the electrical component. So, I had read somewhere to load the slave cylinder with fluid before installation. I did this to the very top. This is done by depressing the plunger and filling the little connection point with fluid and releasing the plunger to allow it to suck the fluid into the unit. The problem was that during installation as the plunger was depressed it spit fluid out which was frustrating and I then got anxious. I then miss aligned the plunger, completely missing the contact point within the transmission. The first time the unit was activated with pressurized fluid it shot the plunger clean out of the Slave cylinder. This left pieces of the Slave cylinder inside the transmission. Fortunately I was able to fish everything out of the transmission, but wasn't easy. So here is my recommendation:

***This is only for a used or rebuilt unit, not a new unit*** No need to fill the unit with fluid before installation. Although I do think it is a good idea to put some fluid into the unit, Maybe 1 only one depression of the plunger so that there is fluid inside the unit. Then carefully install the unit and feel for the depression of the plunger. If fluid comes out it is normal, but since you don't fill the unit, not much to come out. The fluid line is flexible and so move it out of the way so you don't have to manage it during installation. Tighten all bolts. Attach and tighten the fluid line. Be patient. Not a lot of room. You will only be able to turn fluid bolt a quarter turn at a time. Then use INPA to bleed the Clutch. You will need to fill the reservoir and run the clutch bleed sequence. Again. And again. Check the fluid level. Run it again. Until the bleed sequence completes. It will fail a few times as it fills the fluid line and bleeds out the air. Eventually you will get a successful completion of the Clutch Bleed sequence. Check the fluid level again and adjust.

You will also need to Bleed the Actuator and then conduct a complete Adaption of the Transmission. I would recommend completing all of this before you replace all of the panels on the bottom of the car. Once everything is complete and no leaks, replace panels under the vehicle.

As recall you will need the following for the cylinder:
13 mm socket
Long socket extension. Like maybe 2. I used 1 quarter inch extension an adapter and a half inch extension with a quarter inch socket and half inch socket wrench.
11 mm wrench for fluid line.

I think you will need 8mm socket for the panels.

Thank you!

[sapote]

Any pro tips for installing a used slave to avoid this from happening?

Not a pro, but I think this will help: fill the SC with fluid and bleed the air out (air acts like a spring and you don't like a spring pushing in the rod during the installation), then compress the rod to half way (you don't want to install the sc with a full extended rod -- too unstable), then plug the pipe hole with a bolt (use a bolt instead of the pipe) so fluid cannot spit out during stall. After the 2 nuts tighten down, slowly back out the plugging bolt to release the pressurized fluid, then isntall the fluid pipe and do the bleeding.
This will create the load on the rod so it will not compress too easy into the SC and lost contact with the TOB fork, the root cause of flying rod during bleeding.

[Ipeciulis]

I had a slow leak from the SMG reservoir. I changed the SMG reservoir hose but never changed the Oring that goes into the reservoir.
Once that oring was changed there is no more leaking and no more COG light or dropping out of gear.

[flgman1966]

So I think I misunderstood INPA. The issue is with the clutch adaption, not the Longitudinal Acceleration Sensor. The Clutch is out of range. I am guessing that this means the clutch is too worn down. And also that the Yellow Cog is a warning that something will need attention soon, like the clutch? And not necessarily some horrible problem with the pump or other super expensive electronic components?

To summarize, the car is driving 1000% better. During spirited driving the gears are changing. It is not falling out of gear. No jerking. No dropping clutch in traffic with associated jumping. Very smooth actually.

So what are the issues with not being able to adapt the clutch?

Thee only error message in the transmission errors is that Clutch Adaption incomplete.

[eacmen]

So I think I misunderstood INPA. The issue is with the clutch adaption, not the Longitudinal Acceleration Sensor. The Clutch is out of range. I am guessing that this means the clutch is too worn down. And also that the Yellow Cog is a warning that something will need attention soon, like the clutch? And not necessarily some horrible problem with the pump or other super expensive electronic components?

To summarize, the car is driving 1000% better. During spirited driving the gears are changing. It is not falling out of gear. No jerking. No dropping clutch in traffic with associated jumping. Very smooth actually.

So what are the issues with not being able to adapt the clutch?

Thee only error message in the transmission errors is that Clutch Adaption incomplete.

Can you post a screenshot from INPA of the SMG live data view. Should look like this:

[sapote]

Can you post a screenshot from INPA of the SMG live data view. Should look like this:

Funny the translation calls the odd gears as Uneven gears. So German doesn't have Odd word, but just even and not-even for odd?

[eacmen]

Funny the translation calls the odd gears as Uneven gears. So German doesn't have Odd word, but just even and not-even for odd?

Honestly i’m not sure. I was more curious with comparing my data with the op’s data. I haven’t been having any issues with my SMG. So if, in fact, the clutch is warn out I’m curious if there is an indicator in one of these data values that would indicate this.

Its a self adjusting clutch so in theory the throw of the clutch slave shouldn’t change?

[sapote]

Its a self adjusting clutch so in theory the throw of the clutch slave shouldn’t change?

I guess so. But I think the Self Adjust is just a sale pitch, and I don't want it. Why do people care how long or short the SC rod exposed at the biting point? Why it needs to be kept at the same location? In fact, let the rod and its seals gradually move to the new location as the clutch wearing is better: the whole length of the cylinder wall being used instead of just one location against the seals.

[maw1124]

Again, thank you for all the input. I just directed everything you provided and took a couple of things into consideration. After I replaced the starter and took it out for a drive I had trouble with the transmission. When I checked theSMG reservoir it was a little low. So, remembering this I decided to go through the adaption process with INPA. The first step is attach a battery charger. Next step is to Bleed Actuator. I had to do this step about 3 times. The first 2 times I got an error, I didn't note the error. The third, and all subsequent times, it completed successfully. Then I Bled the Clutch. This completed successfully the first time. When I got to the Adaption I got an error every time. I went to the error code area for SMG transmission. I got error 81, estate. I cleared the error. I tried adaption again, and got the error again, I then noticed that in the error notice from the adaption failure I got the same error. Error 81, estate. I checked the SMG errors and only error 81. I am guessing that this is the State of something that is not right. Maybe a Great Position Sensor. Anyone know if I am on the right track?

So I guess I'll start here. At 105k I think it would be odd to need a new clutch. It seems you have a mix of new and old fluid in the system ("revitalized" not replaced), so even with the "new" clutch slave you're still not getting through SMG adaptations, even though the car is doing better. Well, if that's the case, I'd replace ALL of the fluid first, making sure there's no air in the systems (i.e., clear adaptations completely) as my next step. The mere thought of leaving ANY 20 year old fluid in ANY of my cars is a SMDH idea for me. But from your post #35, I'd have to think you're almost there anyway.

maw

[eacmen]

Screenshot from the SMG technical manual below. Basically indicates that "FC" 68 indicates clutch is slipping. I believe this refers to an error code stored in SMG ECU.