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Discussion Starter #1 (Edited)
Hey everyone, as you know ive had continual SMG trans woes over the past 18 months. This is my latest battle. My clutch is slipping badly at cruise speed. Please check out the video below.

This is what happens:

- from a dead start, the clutch engages well w/o issue
- i can shift through all gears and everything is smooth and effortless, car shifts like the day i bought it
- while cruising at regular speeds (roughly about 45 mph) the clutch seems to disengage completely
- you can literally feel the clutch disengage (think about pushing the clutch pedal in on a manual while in gear)
- the RPMs drop down to idle speed, the gear selection remains the same, the gear is still selected as you can see in the video
- if/when you hit the gas pedal say after slowing down a couple MPH, the increased RPMs have zero effect on the speed of the vehicle
- after 2500 to 3000 RPM the clutch finally reengages, but if that RPM band is reached too quickly it cycles through engagement/disengagement quickly (bouncing)
- violent shudder ensues as a result, this doesnt feel healthy for the car/clutch/transmission/rear diff so i take my foot off the gas
- the only way around all this is to engage the throttle slowly to reach 2500 RPM slowly, wait for the clutch to engage then give it full throttle

Work recently completed within the last 1,035 miles, issues began at the 700 mile mark with these new parts:

- New clutch
- New flywheel
- New throw out bearing/clutch release bearing
- New clutch position sensor (OEM) - super expensive for no [email protected] reason btw
- New SMG unit hydraulic fluid (OEM fluid)
- Clutch adaptations performed when these items were installed
- Catless headers
- Rear differential flush and new fluid (OEM fluid)
- Slave clutch cylinder replaced in 2013



What i have done so far for troubleshooting:

- had the clutch adaptions reset (huge thank you to [email protected])
- flashed the TCU with the Euro SMG tune
- reset the clutch position
- brake pad sensor is on as i need new pads, no other issues
- passenger restraint warning on due to seat mat sensor error (been an issue for 2 years now)
* alex used IPNA to read the codes and faults, no engine codes, no transmission codes present other than increase emissions warning due to the new headers - that code was cleared. i plan to have my Eurocharged tune updated soon, but first i need the trans working lol*

^^^ none of these actions taken above improved the situation unfortunately ^^^


What i think is wrong:

- the clutch and flywheel could potentially be misaligned, the car is with my local mechanic now for trouble shooting but id like to crowd source some potential fixes here
- i am removing the sprint booster, i doubt its the culprit but why not? screw it
- [email protected] told me that my battery voltage was low...makes sense given that the car hasnt really been driven in the last 18 months, ill replace that too
- bad clutch position sensor? its brand new from the dealership, but maybe its faulty?


any ideas or informed feedback welcome. thanks!

<iframe width="560" height="315" src="//www.youtube.com/embed/nXNBtCLgFZY" frameborder="0" allowfullscreen></iframe>
 

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Sell it. That thing has given you nothing but issues. I would have cut the cord a while back based on all the issues you've been having.
 

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This kind of nightmare is why I just did the smg pump, clutch, flywheel, release bearing, pivot pin, clutch fork and rear main seal all replaced at the same time. I know very well that I wont have to waste time dropping my transmission more than once to diagnose the problem and save my time from many shop visits.
 

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Discussion Starter #7
Sell it. That thing has given you nothing but issues. I would have cut the cord a while back based on all the issues you've been having.
i cant sell it. it hasnt run properly in over a year and a half dude. august/september will make 2 years lol


plus, im not that kind of business man. when its time to sell it, its gotta be 100% good to go for the next guy. im not gonna set someone up to fail. hopefully it will go to an enthusiast and they will be right back on this board with her some day haha
 

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Hey Chris, I wasn't suggesting doing anything shady. Sell as-is full disclosure is what I was thinking. I know you've had one thing after another with this car but there has to be a point where you cut the cord or keep cutting checks.
 

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Discussion Starter #9
i totally understood you correctly. i just dont want to pawn off my problem on the next guy. plus, at the point...its a pride thing...i wont let this car beat me....tho it has definitely been beating my checkbook. i might be $6k to $7k in by now just in trans repair stuff over the last year and a half. but hey, i knew going into ownership that it was pricey to own/maintain. my issue is the lack of time i get to enjoy her in between breaks lol


on a happier note, my E36 M3 sedan is a riot every day. always starts up and the few problems ive had so far....ive fixed myself in my own garage ;)






Hey Chris, I wasn't suggesting doing anything shady. Sell as-is full disclosure is what I was thinking. I know you've had one thing after another with this car but there has to be a point where you cut the cord or keep cutting checks.
 

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Discussion Starter #10
Chris,

Can you get a laptop with INPA and TeamViewer hooked up to it?


yes, i can get it hooked back up to a computer again. but there werent any engine or trans errors posted other than the 'increased emissions' code when we checked it last.

is there something specifically i should have them pull/read?
 

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yes, i can get it hooked back up to a computer again. but there werent any engine or trans errors posted other than the 'increased emissions' code when we checked it last.

is there something specifically i should have them pull/read?
I can log in remotely with TeamViewer and observe the SMG analog sensor parameters while the clutch is operating. Might be able to give some insight...maybe.

Just had a thought though, low hydraulic fluid level would prevent the pump from holding the clutch steady. Another thought is the bleeding process for replacing the slave cylinder. If I recall correctly, yours blew out and was replaced. I had to run the bleeding process a good 15 times to get all the trapped air out of mine when I changed it.
 

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Discussion Starter #12
hmmm, both good thoughts. ill connect with my guy today and see if we can check the fluid level and potentially bleed the system again and see if that helps.


the real odd thing is it ran perfectly fine for about 700 miles then like total crap all of a sudden. it makes me think a part failed or has come out of alignment...

JColley thanks for your willingness to help out. ill see if we can figure out a way to get the car hooked up and a view link established.
 

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The really weird part is that in your case the smg hydraulic pressure can't be related, unless it's too high. Since the smg controls need to do exactly nothing to make the car keep going, you're already in gear and clutch is released. hmmm

I wonder if there's a leak in the valve which actuates the slave cylinder which is causing it to slowly depress, a master cylinder of sorts? But then why wouldn't the TCU notice it and throw an error, weird.

I'd take jcolley up on his offer and check out the analog readings of the smg, there might be something in there.

edit: On 2nd thought, maybe you have air trapped in the clutch slave which makes not not fully disengage.
 

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Hey guys basically what the SMG is doing is what Chris is saying but its not exactly what Chis is trying to say...


HUH...





Say what??? :S




The SMG will not allow the car to engine brake in gear. When it attemps to decel in any gear 3 and above the SMG releases by pushing in the clutch

When left in gear and the throttle is released, after several milliseconds the SMG depresses the clutch. The transmission does stay in gear.

When downshifting... the throttle will raise the rpms to get the trans into the lower gear but it also keeps the engine from braking by keeping the throttle up, then after a brief moment of the SMG being in gear, while decelerating, the SMG will depress the clutch.

This is the issue, Something is telling the SMG to depress the clutch when the motor is decelerating in gear. This will happen in all gears 3 and above.

If you down shift after the SMG clutch dis-engagement the SMG raises the engine rpms and immediately goes into gear as if there was nothing wrong, and you can even accelerate smoothly without issues. However If you leave it in the selected gear after disengagement and accelerate... there can be and is an issue with the computer matching engine RPMS with the input shaft speed, giving the chugging. Maybe this part is normal as the clutch normally does not disengage and has to re-engage in the same gear unless in first and second gear.... Guess what? This happens in gears three and above!!!

One thing I did notice with the car was that scanner sees the SMG is in reverse when it is in gears 6 and 7. The car itself shows it in the correct gears on the dash.

I also noticed that with the European tune, the SMG will skip gears while driving.

I removed the Sprint Booster... Boy, low speed engagement is 100% better and parking lot driving is improved.

but throttle now appears lazy.

I replaced the accelerator pedal initially thinking it had a dead spot on the accelerator. No changes.

I replaced the trans temp sender to see if it was getting the wrong reading and thinking the computer was thinking the SMG fluid was overheating and causing this issue, but nope not the issue.
 

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im no mechanic but i can tell you the euro smg doesnt skip gears, its dumb but try something flash your tranny with US software 206 and test the car again, maybe you got an incomplete flash the first time, its important to let the car sleep for 45 minutes after the flash is done,

if your smg pump is releasing the cylinder then maybe its about to fail, start by flashing first,
 

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im no mechanic but i can tell you the euro smg doesnt skip gears, its dumb but try something flash your tranny with US software 206 and test the car again, maybe you got an incomplete flash the first time, its important to let the car sleep for 45 minutes after the flash is done,

if your smg pump is releasing the cylinder then maybe its about to fail, start by flashing first,

That is good to know...

This is happening in Auto shift under light loads

Maybe it would be better to keep it in a USA tune. At least stay with a tune we are familiar with here...

And Skipping gears under light loads is actually a very good idea when it can be done, why go threw the unnecessary gears at all? You skip gears in a car with a manual trans under low or no loads.. why not in a smg if it is possible?
 

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okay so I did a little more diagnosing...

I put the selector in S6 and turned the DSC off...

SMG now acts like it should. :confused:

It does not have a ton of engine braking as I think the throttle is still slightly open by the computer but... the motor does not return to idle like it does in S5 and lower and the motor stays in any gear for as long as I keep the foot off the pedal.

I tried turning off the DSC in S5 but it the issue came back.

So I have to say...

What input does the SMG not pay attention to when it is in S6 and the DSC is off?? :confused:
 

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has this problem always existed as of a certain change or did it suddenly manifest? I wonder if some coding is wrong in the TCU or elsewhere and engine braking was somehow coded out?!
 
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