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Discussion Starter #1
2008/03, USA model (SMG)

February/March time frame the following codes displayed on a report while in the shop for unrelated issue:
4FA0 and 4F40
No symptoms, no CEL or other warnings

Starting in May/June, 2019
Symptom: intermittent slipping on harder acceleration in 7th gear. Sometimes (if I insist on the gas) it'd throw the yellow cog, which goes away in a few seconds with no permanent CEL or other fault in the dash.
Codes pulled at that point:
4FA0 CLUTCH (ACTIVATION, POSITION, DEVIATION 51XS)
Advice from a very reputable independent mechanic: start with PLDC sensor (despite missing explicit codes), then slave cylinder replacement and only after that drop the tranny and look into clutch wear-and-tear

I stopped driving the car almost completely at that point, while researching (God! this forum has become my nightly book read - thanks to all who post and especially @jcolley)

Summer trip, kids school, a few long-but-super-easy (highway) drives, and the slipping has crept into 6th, 5th, if I really tried I could slip even in 3rd and 4th gears and has become easier to reproduce - even at smaller acceleration loads.

Took the car to BMW dealership for "second opinion". They advised and I did address pressure accumulator on the hydro unit (car has extended warranty).
After they replaced the accumulator, the car has degraded tremendously.
  • Slippage is horrible at any gear (incl. 1st and 2nd!!) - car is almost impossible to accelerate.
  • Not before I drove 100 m off the dealership lot, it threw a CEL (the "small", "permanent" check engine light at the top of the dash)
I turned around immediately and left the car with them to explain why it has degraded and why the CEL. I also asked for a printout of codes. Old codes are gone (comparing the odometer stamp). New ones are:
  • 2B10: DME: SMG module monitoring, Present: no
  • 279D DME: Power management, closed-circuit current violation, Present: no
  • 5200: SMG: Signal, engine speed, is faulty (DME), Present: no
  • 510C: SMG: Crankshaft sensor, Present: no
  • A06B: CA: Antenna, bumper, Present: YES
  • S 0195: No communication possible with: Telephone control unit, Present: YES
  • A554: Dashboard: No message (telephone), Present: YES
  • 9CC5: LM: No LIN message (RLS), Present: no
  • A46D: CID: CID malfunction due to peripherial, Present: no
  • 9C54: IHKA: AUC sensor
I asked if the system was bled and clutch adaptation procedure(s) were run and was assured positively on both questions, but A) I dont't know how many times they bled - I've seen in my "studies" that @jcolley recommends more than one bleed due to the specifics of the high-pressure system, and B) I didn't see printouts nor I heard details which adaptation steps were done, and if they managed to succeed

While I intend to update the thread with the progress, at this point I'd like to ask a specific question:
  • Why the super-degraded performance in the SMG operation?
  • Why the CEL? (again in my studies I see that the "new" codes from last read may be related to low battery - could that be it or should I be asking more about the CEL?)
  • Looking at odometer reading stamp of each of these new code readouts, they are "new" compared to the code printout from before replacing the accumulator - where did the "old" messages go?
P.S.
I am a geek, fascinated with the design and the performance of that car, and the gearbox in particular. Understanding of the operation and the diagnosis of the SMG has been extremely interesting. I am obviously new to it - have had the car for about 9 months but I was reading up on the SMG in the last year or so. I am setting up an ISTA rig, so I can stop relying on shops to see what the modules are whispering :). Call me mad, but I am kinda happy that I am having all of these problems - as I said I find it very interesting and satisfying tounderstand the inner workings of that system. I miss my beast, though! Can't wait to merge into its seat again.
 

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I believe the answer to your first question about the SMG performance is that the clutch is slipping.

The codes you had first on the SMG are normally related to PLCD sensor or slave cylinder issues but they are usually accompanied by shifting issues and/or SMG in stuck gear.

The other codes non SMG related codes the shop showed you must have been caused by low battery power, I wouldn’t pay too much attention to them. The first codes don’t appear anymore because they were probably erased at the second shop visit.

The only way to confirm clutch wear is to remove the tranny and check the spline and clutch appearance. I would proceed to focus on the clutch. If the plcd or slave cylinder were defective your car wouldn’t have passed the adaptation procedure.









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Discussion Starter #3
I believe the answer to your first question about the SMG performance is that the clutch is slipping.
...
Sure, but why I had nothing more than the YCOG before change of accumulator - I'd get it only if I pushed the car past the limit I was able to feel 100% (meaning I could drive the car 100% error free, if I wanted, on the flat roads of NE PA). And it is almost-un-driveable after the accumulator change?

I am not questioning the fact and I am not suspecting any foul play or anything. I am just trying to build my understanding.

If I have to reason based on what I know, since adaptation hadn't been done for awhile (except my attempts to do the both-peddles thing), doing it now either was not possible (what would be the state of the system if adaptation fails at one of the steps - is it rolled back to previous values or it's "partially adapted"?) or it completed but yielded parameters that are worse, compared to previous. Or is it something else? (Like air in the system)

***
BTW, tomorrow I am talking to them about what else we will be doing while down there (there's always other things to do when one is down there :p)
  • Planning to do the stock clutch; flywheel only if needed, cryo-treated TO bearing, brass pin, etc.
  • QUESTION: I still need to research flywheel dowel
  • QUESTION: seal rings of "clutch valve" mentioned here: gasket rings for the clutch cylinder - what is "clutch valve" - the slave? What seals are mentioned? Is this reconditioning instead of replacing of the slave?
    Also another poster is mentioning it like this: "don't forget to "change all ... gasket rings for the clutch cylinder"
  • Will most likely do the rear crankshaft seal and bearing
  • QUESTION: should I do the crankshaft/speed sensor?
  • Transmission mounts
  • Shaft seals in the tranny
  • UNDECIDED - should I try to refresh the pump motor preventively?
  • Oil lines/banjo bolts - inspect
  • ... a bunch of other exhaust, diff and shaft stuff
I have part numbers and some internet-sourced prices, if someone is interested. I would also welcome quotes if parts guys are reading this.

Thanks
 

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Voltage regulator going bad, common issue and $30 part


Clutch deviation codes usually involve the clutch control valve solenoid, new viton rings is usually all that is needed. That and swap the chf11s fluid.
 

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Sure, but why I had nothing more than the YCOG before change of accumulator - I'd get it only if I pushed the car past the limit I was able to feel 100% (meaning I could drive the car 100% error free, if I wanted, on the flat roads of NE PA). And it is almost-un-driveable after the accumulator change?

I am not questioning the fact and I am not suspecting any foul play or anything. I am just trying to build my understanding.

If I have to reason based on what I know, since adaptation hadn't been done for awhile (except my attempts to do the both-peddles thing), doing it now either was not possible (what would be the state of the system if adaptation fails at one of the steps - is it rolled back to previous values or it's "partially adapted"?) or it completed but yielded parameters that are worse, compared to previous. Or is it something else? (Like air in the system)

***
BTW, tomorrow I am talking to them about what else we will be doing while down there (there's always other things to do when one is down there :p)
  • Planning to do the stock clutch; flywheel only if needed, cryo-treated TO bearing, brass pin, etc.
  • QUESTION: I still need to research flywheel dowel
  • QUESTION: seal rings of "clutch valve" mentioned here: gasket rings for the clutch cylinder - what is "clutch valve" - the slave? What seals are mentioned? Is this reconditioning instead of replacing of the slave?
    Also another poster is mentioning it like this: "don't forget to "change all ... gasket rings for the clutch cylinder"
  • Will most likely do the rear crankshaft seal and bearing
  • QUESTION: should I do the crankshaft/speed sensor?
  • Transmission mounts
  • Shaft seals in the tranny
  • UNDECIDED - should I try to refresh the pump motor preventively?
  • Oil lines/banjo bolts - inspect
  • ... a bunch of other exhaust, diff and shaft stuff
I have part numbers and some internet-sourced prices, if someone is interested. I would also welcome quotes if parts guys are reading this.

Thanks
It’s hard to say but the clutch was definitely on it’s way out before the change, the new accumulator would have restored the pressure accumulation capacity of the unit then causing added stress to older parts i.e. clutch. Its a very simplified explanation but there might bot be a straight answer for this one.

The adaptation procedure is focused on bleeding and calibrating the clutch valve (aka slave cylinder) and calibrating the gear changes rather than testing clutch life or performance.

The slave cylinder is basically a piston driven by hydraulic pressure, the lines going in and out of the valve have 2 aluminum o rings each per banjo bolt. These rings are what is being referred to as gaskets. It is recommended to replace them all but they can also be lightly sanded to restore flatness and reused.

If you have enough cash and you are totally depend on a shop to do the work I would do the clutch, TO bearing, slave, plcd sensor, hydraulic pump and maybe the crank sensor, flywheel can stay as long as it is within spec.

Il not sure the rear main seal can be replaced though, these engines have a split upper and lower block that is held together by a sealant and it goes straight through the rear main. Don’t take my word for it and do research on it.



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From your description, clutch adaptation wasn't done right. Or faulty slave/clutch position sensor. Or, maybe your clutch is completely gone. Maybe I missed it - how many miles on the car?
 

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Discussion Starter #7
Shop would not say if all adaptation steps completed. Car has 105K now - I've had it for about 8K. No clutch job in prior history as far as I could see at the BMW dealership which sold it to me as a trade-in. But last 20-30K of history seem to be at independent so they're an unknown.
 

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Could be the clutch then. I'd start planning for it - flywheel, pressure plate, TB, guide bush, fork, pivot pin, slave. I'd do at least that if the box is down.
 

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Discussion Starter #9
An update: awaiting on extended warranty if they will authorize the repair, since it's caused by faulty SMG operation.
 

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Discussion Starter #10
I could not find a definitive number for labor to replace the clutch. BMW dealership are quoting 9 hours, but I seem to remember seeing 6.

Does anybody have the book value for that job?
 

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Between 6-9 hours sounds about right. The dealer will obviously quote the maximum amount of hours.


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Discussion Starter #14
Update: awaiting parts and starting the job on Mon.

Question: I was able to get a slave cylinder off of ebay for the old" price of arounf $300. How can I verify if it's Genuine BMW (as it was advertised)?

Also, I know that the fork pin and the clutch bushing are "upgraded" by aftermarket suppliers - respectively made of bras (instead of plastic) and cryo-forged. But dealership is not willing to warrant their work if I use "aftermarket" parts. They are otherwise giving me 2 years parts/labor, so I am leaning towards using Genuine BMW to get the warranty. Anybody with a concrete experience with these two parts?
 

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Update: awaiting parts and starting the job on Mon.

Question: I was able to get a slave cylinder off of ebay for the old" price of arounf $300. How can I verify if it's Genuine BMW (as it was advertised)?

Also, I know that the fork pin and the clutch bushing are "upgraded" by aftermarket suppliers - respectively made of bras (instead of plastic) and cryo-forged. But dealership is not willing to warrant their work if I use "aftermarket" parts. They are otherwise giving me 2 years parts/labor, so I am leaning towards using Genuine BMW to get the warranty. Anybody with a concrete experience with these two parts?
I don’t think there are aftermarket slave cylinder options in the market so I wouldn’t worry. As for the bushings I have no experience on those.


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Discussion Starter #17 (Edited)
Flywheel:
From the limited knowledge I have the smaller darker spots aren't too big of a concern? We're yet to clean it and see if there are large heat spots.
Shop was not concerned with play.
Is there anything else that would indicate heat damage other than visual on the surface?

Oil at bottom ob bell housing:
I have asked them to get to the seal because of this oil present at the bottom - is there anything else that may be contributing to that leakage? (picture coming...)
932438
 

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Final update:
Oil was from crank seal. That was great news for me, as it meant that my basic aftermarket warranty will cover labor for dropping transmission and fixing it.

Happy to report that repair turned out pretty well and about 500 miles later everything seems to be as expected.

Contrary to others' experiences and also mine past ones, dealing with dealership was as good as I could imagine it*. I'll give a huge thumbs up to Tyler and the tech team at Princeton BMW (New Jersey).

Got a heart attack the night they put the transmission back - the SA left me a message that "Slippage is gone, car runs strong, but they didn't replace the seal." - yes - I the only seal we discussed replacing was the one from the picture above - the one that leaks oil and the one that is the basis for the warranty to cover some of the labor for dropping the transmission!!!!! After I grayed my hairs for a night, it turned out the SA was talking about the seals on the tranny shaft, which at some point early on I must have mentioned that I'd look into replacing "while there".
____
* As I mentioned in a previous post, they didn't want to deal with solenoids o-ring replacement.
 

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What is the average lifespan of an SMG clutch? For mostly normal driving with of course some spirited runs mixed in but no road racing. Previous owner had it replaced at 63k and I'm at 111k now. Seems to be chattering a bit more lately, especially in 2 starting off after a slow roll.
 
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