Jerky gearbox at low speeds - Page 2

VitaminT · 07-28-2007

My tranny shifts awsome, but I too get the harsh downshift when coming to a stop. Not sure if it is 3-2 or 2-1 but I will check in manual mode. This while in S-mode andI havent used C in some time.

I get tons of people that comment on how smooth the tranny is. Not sure if it is the 7 speeds make shifts less apparent or what.

DansSlk · 07-28-2007

Quote:

Originally Posted by daj

Yep, get the jolt when in Manual Mode, but only when shifting down to 2nd, manual shifting through others gears is seemless, hardly noticeable at all. I think the jolt is about the same strength, but do find the jolt is more pronounced when I am braking to slow down coming to a junction etc, than letting the car roll to a stop.

I will test out the Parking prawl issue soon, thanks.

OK mate,

It does sound like a valve on the way out to me especially if its getting worse.

With the park prawl test i have made a change to it so just give it a quick read again, messed up R and N in the pulling away part.

DansSlk · 07-28-2007

Neither of my transmissions has given me any harsh shifts.

Fair enough the first one seized but it was shifting fine up until then.

It could be related to break-in and thats why a reset of the box fixes the problems but the computer should smooth things out as the mileage increases if the problems get worse i can almost guarantee its a mechanical fault.

The fault itself might not be causing the bad shifts but the computer trying to compensate for it can have knock on effects.

Always have the dealer reset the box before doing anything else to it then drive the car like you stole it for a few weeks and if its not better by then its only going to get worse.

A little known quirk is that during gearbox programming the unit must be taught each shift i.e 1-2 2-1 etc, this is done on the road normally and if a bad shift occurs say the tech shifts at a bad RPM or approaches a stop light and has to shift down rapidly those initial patterns will be stored so you can drive for years building the profile but if the initial few shifts have any weird patterns to them the gearbox will not properly adapt and you will get a harsh shift because the way it shifts is a copy of the initial one made by the tech.

So if he changes at the wrong RPM and causes a rev spike the car will also tend to cause spikes during that particular shift maneuver.

suntan · 07-29-2007

Hi, DansSLK! Thanks so much for your response! I'll have it looked at asap (I'm going in for that 1k-3k introductory service thingy anyway). Unfortunately, I've been told repeatedly that the dealerships here in Boston are incompetent.

I was actually going to have all my car needs serviced by a reputable independent shop (recommended by someone on BenzWorld, actually). You wouldn't happen to know which of the Boston/Massachusetts service centers have the best reputation, would you? Thanks so much, mate!

cheers,
suntan

DansSlk · 07-29-2007

Sorry mate can't help on that one i live in the UK so dont know who's who in the US.

Sorry

daj · 08-01-2007

Quote:

Originally Posted by DansSlk

OK mate,

It does sound like a valve on the way out to me especially if its getting worse.

With the park prawl test i have made a change to it so just give it a quick read again, messed up R and N in the pulling away part.

Hi Dan, tested the park prawl, and your suggestion worked a treat, no clunk when applying the handbrake before putting the gear into P, thanks.

DansSlk · 08-01-2007

Quote:

Originally Posted by daj

Hi Dan, tested the park prawl, and your suggestion worked a treat, no clunk when applying the handbrake before putting the gear into P, thanks.

Cool what happens when you put it back into R should be no clunk then either

ppower · 08-01-2007

I have had this problem too. It is mostly noticeable in "s" mode. In "c" mode I don't notice it(it has happened a few times in "c" mode, but only after some very spirited driving while in "c" mode then coming up to a light, it's like the transmission is trying to act like "S" mode since I am driving like I would be in "S" mode). I took the car to the dealer when I first got it (2nd owner picked it up with 11k miles on it). The tech at the dealer was very helpful. He stated that in "S" mode the car will downshift into 1st and in "C" mode it doesn't. In "S" mode the downshifts are programmed to be a bit more sharp and preemptive. They took and tested the transmission and reset it so it could learn my driving habits. He stated the transmission is borderline on it's defined parameters. But, if the reset didn't result in making me happy with how it performs they would replace the tranmission with a new one, it would just need to be the shop a few days to a week. I have just over 16k miles on it now and I don't have any problems in "C", but "S" still seems to me to downshift into 1st too early, thus causing a slight jolt when slowing at a light. My biggest concern with this is someone rearending me coming up to a light since this jolt causes the car to slow abruptly 3-4 car lengths short of where I will come to a complete stop.

I am thinking when I get about 20k+ miles on the car I will take them up on putting in a brand new transmission.

Pp

DansSlk · 08-01-2007

Its a very generous offer for them to make but unless they plan on paying for it themselves i doubt it will happen before MB will pay they will want diagnostic reports and if it shows a repairable fault then they will have them just replace the damaged parts.

Most likely the valve thats controlling first gear

**webslinger** · 08-01-2007

Quote:

Originally Posted by OWL-SLK

I´m sorry to say but just up to 2007 the 7g is free of mistakes, the former models have had problems, but with the new software* it should be gone. If not there´s something wrong with the gearbox itself.

* - some dealers don´t know which version is the newest...

My 1 month old '07 had it a couple of times but with 960 or so miles on it it seems to have gone away. It's a very harsh drop from 3rd to second at under about 5 mph.

DansSlk · 08-01-2007

Quote:

Originally Posted by webslinger

My 1 month old '07 had it a couple of times but with 960 or so miles on it it seems to have gone away. It's a very harsh drop from 3rd to second at under about 5 mph.

Thats the software.

Once it goes it wont come back again, no need to worry about it.

daj · 08-01-2007

Quote:

Originally Posted by DansSlk

Cool what happens when you put it back into R should be no clunk then either

Sorry, that's what I meant to say. Put it into N, then apply handbrake before putting gear into P. Then upon returning to the car when I select R, no longer get the loud clunk due to the parking prawl.

DansSlk · 08-01-2007

Quote:

Originally Posted by daj

Sorry, that's what I meant to say. Put it into N, then apply handbrake before putting gear into P. Then upon returning to the car when I select R, no longer get the loud clunk due to the parking prawl.

Ah OK mate.

Glad thats sorted for you, it's not hurting the tranny at all so don't worry about that bang the problem is it basically being wedged into the teeth with all the weight of the car locking it there and it just takes some force to pop it out.

ppower · 08-02-2007

Quote:

Originally Posted by DansSlk

Its a very generous offer for them to make but unless they plan on paying for it themselves i doubt it will happen before Mercedes Benz will pay they will want diagnostic reports and if it shows a repairable fault then they will have them just replace the damaged parts.

Most likely the valve thats controlling first gear

The tech stated it would be covered under warranty and he also told me they would put in a brand new one as per Mercedes-Benz they are not allowed to repair or rebuild the 7-speed auto. If I remember correctly too, he stated they ship the old trans back to Germany.

Pp

My dealer is very cool, the tech replaced the passenger mirror turning signal assembly under warranty for a hairline crack that had formed in the bottom of the lens.

DansSlk · 08-02-2007

I don't mean to argue and i really hope you do get a new tranny if / when you decide on replacing this one but the comment about not being allowed to repair it is just plain wrong.

All of the parts are available separately and the TSB says that you are only to replace the damaged parts, people who have had the TSB carried out will be able to confirm.

Are you sure they replaced the whole mirror unit just for a damaged lens?

iPPi · 08-02-2007

I noticed this on mine as well, and I just got my car about 2 weeks ago. Only got 600 km on it and it's still noticeable.

DansSlk · 08-02-2007

Quote:

Originally Posted by iPPi

I noticed this on mine as well, and I just got my car about 2 weeks ago. Only got 600 km on it and it's still noticeable.

Hey welcome to the site.

Yours will be software at the moment the more you drive the less noticeable it will become as the computer adapts it out

ppower · 08-03-2007

Quote:

Originally Posted by DansSlk

I don't mean to argue and i really hope you do get a new tranny if / when you decide on replacing this one but the comment about not being allowed to repair it is just plain wrong.

All of the parts are available separately and the TSB says that you are only to replace the damaged parts, people who have had the TSB carried out will be able to confirm.

Are you sure they replaced the whole mirror unit just for a damaged lens?

Yep, the tech flat out stated they are not allowed to repair or rebuild that transmission yet(dealer is Continental Motorcars in Melbourne, FL Service#1-800-719-6638 http://www.continentalmotorcars.com/service/index.htm). They just pull them and replace it with a new one. Who knows it might be some kind of union thing. I thought it was strange also that they can't repair them (I am familiar with the auto parts industry I used to work in it for a whole sale company that sold auto body parts to body shops when I was in school).

As, for the mirror might have just been the lens, but the labor is all the same they had to take it all apart to do it and it didn't cost me a dime and it got fixed and they didn't bust my balls about it...which is all that really matters in the end.

DansSlk · 08-03-2007

Well hopefully yours will be sorted before MB hits them with the chargeback then mate.

Have they ever messed up? Just curious because to remove the mirror housing you need to remove the glass so if thats all that they where replacing then it would have been the first thing out.

As you say so long as it's not costing you anything then its not really a problem

ppower · 08-03-2007

Quote:

Originally Posted by DansSlk

Well hopefully yours will be sorted before Mercedes Benz hits them with the chargeback then mate.

Have they ever messed up? Just curious because to remove the mirror housing you need to remove the glass so if thats all that they where replacing then it would have been the first thing out.

As you say so long as it's not costing you anything then its not really a problem

Only had to take the car there once so far. And basically it was to get the transmission flashed and to have the mirror fixed. They put on new wipers too for free. It was right after I got the car.

Question: My car states that it's 90 days over due for Service E, but the car only has 16k miles on it. And according the service schdule my next service isn't due until 20k miles. Does it just post being over due based on days? I got the car with 11k and the dealer said they just serviced it at 10k miles when I had bought it(dealer that sold me the car was same that sold it to the original owner).

Thanks

Pp

07-28-2007	#23 (permalink)
DansSlk Dude Join Date: Jun 2006 Location: Wales Vehicle: 05 B55S (Brabus 6.1 S) Posts: 6,756 Country: Thanks: 96 Thanked 221 Times in 173 Posts	Neither of my transmissions has given me any harsh shifts. Fair enough the first one seized but it was shifting fine up until then. It could be related to break-in and thats why a reset of the box fixes the problems but the computer should smooth things out as the mileage increases if the problems get worse i can almost guarantee its a mechanical fault. The fault itself might not be causing the bad shifts but the computer trying to compensate for it can have knock on effects. Always have the dealer reset the box before doing anything else to it then drive the car like you stole it for a few weeks and if its not better by then its only going to get worse. A little known quirk is that during gearbox programming the unit must be taught each shift i.e 1-2 2-1 etc, this is done on the road normally and if a bad shift occurs say the tech shifts at a bad RPM or approaches a stop light and has to shift down rapidly those initial patterns will be stored so you can drive for years building the profile but if the initial few shifts have any weird patterns to them the gearbox will not properly adapt and you will get a harsh shift because the way it shifts is a copy of the initial one made by the tech. So if he changes at the wrong RPM and causes a rev spike the car will also tend to cause spikes during that particular shift maneuver. __________________ One thing you will learn with German cars - If it's simple it ain't happening.

07-29-2007	#25 (permalink)
DansSlk Dude Join Date: Jun 2006 Location: Wales Vehicle: 05 B55S (Brabus 6.1 S) Posts: 6,756 Country: Thanks: 96 Thanked 221 Times in 173 Posts	Sorry mate can't help on that one i live in the UK so dont know who's who in the US. Sorry __________________ One thing you will learn with German cars - If it's simple it ain't happening.

08-01-2007	#29 (permalink)
DansSlk Dude Join Date: Jun 2006 Location: Wales Vehicle: 05 B55S (Brabus 6.1 S) Posts: 6,756 Country: Thanks: 96 Thanked 221 Times in 173 Posts	Its a very generous offer for them to make but unless they plan on paying for it themselves i doubt it will happen before MB will pay they will want diagnostic reports and if it shows a repairable fault then they will have them just replace the damaged parts. Most likely the valve thats controlling first gear __________________ One thing you will learn with German cars - If it's simple it ain't happening.

08-02-2007	#35 (permalink)
DansSlk Dude Join Date: Jun 2006 Location: Wales Vehicle: 05 B55S (Brabus 6.1 S) Posts: 6,756 Country: Thanks: 96 Thanked 221 Times in 173 Posts	I don't mean to argue and i really hope you do get a new tranny if / when you decide on replacing this one but the comment about not being allowed to repair it is just plain wrong. All of the parts are available separately and the TSB says that you are only to replace the damaged parts, people who have had the TSB carried out will be able to confirm. Are you sure they replaced the whole mirror unit just for a damaged lens? __________________ One thing you will learn with German cars - If it's simple it ain't happening.

08-03-2007	#39 (permalink)
DansSlk Dude Join Date: Jun 2006 Location: Wales Vehicle: 05 B55S (Brabus 6.1 S) Posts: 6,756 Country: Thanks: 96 Thanked 221 Times in 173 Posts	Well hopefully yours will be sorted before MB hits them with the chargeback then mate. Have they ever messed up? Just curious because to remove the mirror housing you need to remove the glass so if thats all that they where replacing then it would have been the first thing out. As you say so long as it's not costing you anything then its not really a problem __________________ One thing you will learn with German cars - If it's simple it ain't happening.

07-28-2007	#21 (permalink)
VitaminT Elite SLK World Member Join Date: Apr 2007 Location: Alabama Vehicle: 2005 SLK55 Posts: 361 Country: Thanks: 0 Thanked 0 Times in 0 Posts	My tranny shifts awsome, but I too get the harsh downshift when coming to a stop. Not sure if it is 3-2 or 2-1 but I will check in manual mode. This while in S-mode andI havent used C in some time. I get tons of people that comment on how smooth the tranny is. Not sure if it is the 7 speeds make shifts less apparent or what.

07-29-2007	#24 (permalink)
suntan SLK World Member Join Date: Jul 2007 Location: Boston Vehicle: '06 BMW 330i, '06 MB SLK350 Posts: 41 Country: Thanks: 0 Thanked 0 Times in 0 Posts	Hi, DansSLK! Thanks so much for your response! I'll have it looked at asap (I'm going in for that 1k-3k introductory service thingy anyway). Unfortunately, I've been told repeatedly that the dealerships here in Boston are incompetent. I was actually going to have all my car needs serviced by a reputable independent shop (recommended by someone on BenzWorld, actually). You wouldn't happen to know which of the Boston/Massachusetts service centers have the best reputation, would you? Thanks so much, mate! cheers, suntan

08-01-2007	#28 (permalink)
ppower Senior SLK World Member Join Date: Feb 2007 Location: Central FL. Vehicle: 05' SLK55 Orion Blue Other Toys: CBR600rr, Mustang SC 480hp Posts: 118 Country: Thanks: 3 Thanked 4 Times in 1 Post	I have had this problem too. It is mostly noticeable in "s" mode. In "c" mode I don't notice it(it has happened a few times in "c" mode, but only after some very spirited driving while in "c" mode then coming up to a light, it's like the transmission is trying to act like "S" mode since I am driving like I would be in "S" mode). I took the car to the dealer when I first got it (2nd owner picked it up with 11k miles on it). The tech at the dealer was very helpful. He stated that in "S" mode the car will downshift into 1st and in "C" mode it doesn't. In "S" mode the downshifts are programmed to be a bit more sharp and preemptive. They took and tested the transmission and reset it so it could learn my driving habits. He stated the transmission is borderline on it's defined parameters. But, if the reset didn't result in making me happy with how it performs they would replace the tranmission with a new one, it would just need to be the shop a few days to a week. I have just over 16k miles on it now and I don't have any problems in "C", but "S" still seems to me to downshift into 1st too early, thus causing a slight jolt when slowing at a light. My biggest concern with this is someone rearending me coming up to a light since this jolt causes the car to slow abruptly 3-4 car lengths short of where I will come to a complete stop. I am thinking when I get about 20k+ miles on the car I will take them up on putting in a brand new transmission. Pp

08-02-2007	#36 (permalink)
iPPi SLK World Junior Member Join Date: Jul 2007 Vehicle: '07 SLK 350 Posts: 3 Country: Thanks: 0 Thanked 0 Times in 0 Posts	I noticed this on mine as well, and I just got my car about 2 weeks ago. Only got 600 km on it and it's still noticeable.