Guys I've searched on this and while there's a few members reporting the problem, I've yet to find anyone post a successful resolution.

My story: 2012 Performance Pack Coupe, with 120,000km, zero modifications.
There's clutch slip with momentary engine speed flare in every gear when accelerating from under 2000rpm, in all transmission modes. There is ZERO slip above 2000rpm.
With standing starts from 1st gear at moderate throttle the transmission hooks up without slip ( probably because engine speed rapidly ascends beyond 2000rpm), but there's a judder which feels similar to "old school" axle tramp ( but clearly isn't).

Dealer has performed the following:
Checked fault codes - none
Updated to latest software - no impact
Performed re-adaptation - no impact
Carried out smoke test for inlet manifold issues - very minor leak. Corrected - no impact
Replaced entire clutch pack and clutch solenoid valve - FIXED!!! But 5000km later, it's back, as bad as ever.

For what it's worth, I mostly drive in manual mode, except in heavy traffic. Aside from clutch slip, all changes are rapid - there's no delay in response to paddles.

Any thoughts on this incredibly annoying ( and costly!) issue??

 

I am speculating here, but it could well be clutch pack wear resulting from you mostly driving it in M. The transmission shift times in M are the quickest / most aggressive, with the shift completed in 100 ms. 100 ms is not enough time for the engine speed (revs) to either drop or rise to whatever the engine speed would need to be for the next gear you've selected, so there's ALWAYS significant clutch slip at every gear change - which doesn't happen in C or S. It's no different that you doing 20+ race starts... the clutch pack is only good for 10 or 15 at the most. I can't think of another reason.

 

Thanks Diabolis. I've no doubt using manual most of the time must increase loads on the transmission. However if clutch pack failure is the issue, its hard to understand why the original pack lasted around 120,000km, but the replacement only 5000km. Gut feeling is something else is going on here....

 

Actually... scratch that. If it was wet clutch pack wear, chances are it would be slipping even more at higher revs / torque. If the flare only happens at low revs, it sounds like the issue is transmission fluid pressure related as the transmission is not able to supply the correct clutch pack fill times and pressures Assuming it is not a TCU adaptation issue, clogged solenoids or valve body?

 

Cheers Diabolis. This sounds like it might be the right track....

 

In the same boat with the same issues as OP ... have yet to figure this out .

 

Well for anyone interested - this ended badly. My car has been at the dealer service center for the past 5 weeks. Problem was eventually referred to AMG Germany, who logged directly in to the ECU. No significant anomalies detected. Germany recommended the solenoid - replaced 5000km ago - be replaced again. No improvement. They then suggested replacing the entire valve body. No improvement. A technician was then sent from Mercedes Australia Head Office to consider whether the transmission should be rebuilt or replaced. They advised it's too old to rebuild. It must be replaced with a "remanufactured" OEM transmision at a cost of around Aussie $10,000 ( about US$6800), and I must wait another 3 weeks + for the "new" transmission to arrive. The only positive in all this is that I have a dealer loan car for the entire duration.

For me it's a very, very disappointing outcome. This is the only car I have ever kept for more than 5 years, because I still love driving it. I had made up my mind to keep it indefinitely, because a meticulously well maintained and cared for Merc V8 should last a long time, right? I saw myself down the track as "that old guy with 400,000km on his Benz". The last of the great NA V8's etc etc.
Multiple costly failures in recent years now have me seriously doubting this plan.

 

If poster wants to thrash his auto car like this,, then he should have purchased a manual shift .

 

Take the opportunity to get a built trans kit? Have a trans specialist install it.

 

How amusing and insightful OptimusprimeM1.

 

Were they able to pinpoint the failure? What exactly was the problem that the transmission had to be replaced, instead of just parts of it?

Also, surely you could source a new transmission for less yourself... Or buy a built one for nearly the same price they are asking. Is this all being done under warranty?

 

Does manual shifting mode really increases wear in trans components by this much ? Unbelievable !

 

Essentially after trying what they thought were all the logical parts to replace, nothing worked. They were left with either a complete strip down and rebuild or replace with AMG remanufactured transmission. They say it’s more economic to do the latter as all worn components are already replaced.
I doubt it’s possible to buy and install a new MCT for anything like this money, but I may be wrong.

No warranty unfortunately- car is nearly 8 years old.

 

Yeah I’m surprised too. We don’t actually know if it’s the manual shifting that contributed to the problem, but since hardly anyone else seems to have faced the same issue here, maybe manual IS the cause.

 

A friend here said to me once that 2 cars, same model, same year, same specs, could be completely different in power outputs. I thought he was crazy, as he went further to state that one could be 100% pristine built, and other full of defects - even though brand new. Any chance yours left factory with some problem already? Not that it's relevant at this point, but it's very weird that you dug that deep into the possible problems, and still couldn't find what was wrong with it exactly. Hoping it's all going to sort out in the best (and less expensive way) possible, OP.

 

Thanks for the positive vibes Vpatriota :-)
Can't rule out a defect from the factory I guess, but I suspect not as the transmission was perfect right up to 120,000km when the fault became apparent.

 

 

My 2013 S204 does the same but only when cold.
Once warm/hot it shifts fine at all times.
I had the oil changed 2018 and have travelled around 15,000 klm.
It has been suggested that maybe the fluid level is a little on the low side but once hot its fine due to expansion of the trans fluid.

 

Hopefully he didn’t just sell it

 

Hi Lumr the full outcome is in response #7 above. The swapped AMG remanufactured transmission works fine. I've reluctantly accepted I need to let it do its own thing in Auto S or S+ mode most of the time rather than use in Manual to the extent I used to. I still love the car and intend to keep it, and I'm hoping for a trouble-free run after a string of costly problems in the past 2 years.

 

Slip when warm here on a 2013 57k. Maybe there’s a case for a recall/law suit as there’s seems to be so many.