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Looks like my C450 has joined the rough 2nd gear club...
I have a little over 3,000 miles on my 2016 C450, and for the past 500 miles or so I've notice a really rough shift around 2nd gear when the transmission is fully warmed up...and when traveling slowing, like when stuck in stop n' go traffic.
I equate the rough 2nd gear shift feeling to a manual transmission when one lets the clutch up too quickly after changing gears...more like a lurch. I've read there are transmission reflashes or replacement torque converter modules that might do the trick.
I made an appointment to drop the car off at the dealership this Friday...I'll let everyone know how things go.
Same issue here. I've tracked it down to the fact that the car stays in 2nd gear for less than a second or two under normal acceleration from a stop. The shift from 2->3 is definitely jerky on its own but I think combined with the fact that you experience the 1-2 shift followed almost instantly by the 2-3 shift amplifies the issue even more. I've tried resetting adaptive transmission and took it to the dealership but they claim that they ''can't identify an issue'' and that it's normal for the w205.
At least I think it's a 2nd gear issue. I don't know why the C450 doesn't display the gear number when in "Comfort mode" for instance like my 2015 C300 did. All I know for sure is when stopped, an "arrow" appears next to "P", but after the vehicle starts moving and makes it's first gear change, the arrow disappears...then nothing.
Hate to say it, but this rough gear change in 2nd is annoying enough for me to look else where when shopping for my next car...if Mercedes doesn't have a fix. Even my 2015 C300 had this issue, but not as bad.
My wife's 2017 Jaguar XE R-Sport with the same 8 spd as a BMW shifts flawlessly.
It's not a shift. It's your 2nd gear slipping and it's at its worst when transmission oil is fully warmed up.
Put the car in manual mode. Shift into 2nd gear at a stop. Now start moving as you normally would and right around 2000rpm it will slip and drop a couple hundred rpm and then continue back up the rev range normally.
When not in manual mode it's hard to tell because you don't know what gear you're in so it feels like a rough shift. Putting it in manual let's you see what gear it's in and you can see the slip.
Doesn't feel as bad if the car starts in 1st as it misses the slip point by the time it shifts.
I personally like to start in 2nd gear because I don't like how it shifts into 1st gear before the car comes to a complete stop.
Whatever it is...it's annoying as hell, and it's the only gear that I feel it. The rest of the higher gears are fine. Would be nice if Mercedes included the gear number indicator in the C450.
Anytime (once the car is fully warmed up) I start slowly accelerating from a stop, I feel this jerky shift in what seems like 2nd gear...enough that the car seems to "bounce" slightly back n' forth...like a poorly made shift change in a manual. The car did not do this until recently.
It's not a shift. It's your 2nd gear slipping and it's at its worst when transmission oil is fully warmed up.
Put the car in manual mode. Shift into 2nd gear at a stop. Now start moving as you normally would and right around 2000rpm it will slip and drop a couple hundred rpm and then continue back up the rev range normally.
When not in manual mode it's hard to tell because you don't know what gear you're in so it feels like a rough shift. Putting it in manual let's you see what gear it's in and you can see the slip.
Doesn't feel as bad if the car starts in 1st as it misses the slip point by the time it shifts.
I personally like to start in 2nd gear because I don't like how it shifts into 1st gear before the car comes to a complete stop.
If these cars are actually slipping, the clutch packs need to be replaced.
Plain and simple.
I would be very surprised if there's still an old fashioned torque convertor in these trannies.
But, you never know....
I was able to drop my C450 off tonight instead of tomorrow morning, and while talking to the service advisor, right off the bat he said there's a reflash for that...which made me hold on to hope that there's a fix for this. As long as there's a reduction in the harsh shift, I'll be happy.
What was also cool is I was given a new 2017 C300 coupe for a loaner!
There are clutch packs in every gear, the AMG trans has a wet clutch torque converter, but every gear in the transmission has friction materials/clutches that engage when it goes into that gear.
If you're getting slippage when already in a gear, it probably needs a transmission. That's what warranty is for.
There are clutch packs in every gear, the AMG trans has a wet clutch torque converter, but every gear in the transmission has friction materials/clutches that engage when it goes into that gear.
If you're getting slippage when already in a gear, it probably needs a transmission. That's what warranty is for.
That's what I thought....
Old school transmissions had a single torque convertor.
Newer transmissions have clutch packs, dry or wet, usually a couple if not multiples, like the AMG to provide faster shifting, which allows gears to be "on deck"....
If you are getting this kind of slippage, the transmission is either shot - OR, alternatively, there could be a software update to resolve, but that's highly unlikely. I saw it resolve something once temporarily in my old S6, but it was just temporary as it readapted and then immediately reverted back to the old behavior.
You're talking DCT which is effectively two gearboxes in one. That's not the same as a torque converter with a single lockup clutch.
I'm talking about the gears in any automatic transmission. The newer DCT is essentially a pair of automatically clutched and shifted manuals squeezed together. Non-DCT automatics use fluid to apply packs of friction discs, also called clutches, to engage each gear. 1st gear has a clutch pack to transfer power. When second is desired, solenoids move the fluid pressure to the second gear pack and it engages. This is all in the transmission, not the torque converter. The traditional torque converter has a "clutch" added simply to lock it up for highway cruising efficiency. The AMG "MCT Speedshift" transmissions and similar replaced the fluid based power transfer of the old style torque converter with a wet clutch pack, similar to a motorcycle design, to allow complete decoupling of the drivetrain for rapid shifting (a traditional torque converter always puts power into the transmission)
Well, got my C450 back from the dealership this morning...good news and meh news about the rough 2nd gear shift...
The good news, the dealership seems to have fixed the dashboard/binnacle creaking I had also complained about when I dropped off the car, they even were proactive and addressed a known issue with the trim around the pano roof...good job MBOB! The work involved removing the Comand screen and applying felt tape or lubricant to the contact areas including the dash, binnacle, and trim around the pano sunroof.
As for the "meh" news about the transmission...they did hook up their scanning device to the car, found no faults, discovered no updates for the transmission or engine management system for my VIN...but they did perform a "Adaptive" reset and carried out an "Adaptive Drive". I have to say the car seems to drive smoothly like it did when I first took delivery with only 20 some odd miles on it, so I know the car wasn't ever abused, and I certainly haven't abused it since either.
So in the end, the dashboard/binnacle creaks seem to be gone, the tranny shifts smoothly again, and they told me to just bring it back to them if the rough shifting returns. Fingers crossed it stays this way!
Oh, and on a side note...after spending a couple days with the 2017 C300 coupe loaner the dealership gave me, a warning for all you people who have ordered the new coupe...expect to hear a lot of wind/road noise coming from the side windows/seals at highway speeds. WAY more than I ever experienced in my old 2015 C300 Sport sedan or my current C450.
You seem to know about these c450 transmission issues more than most. I have a question:
Do these issues people are having ever come out of the blue? Like say, 10,000 miles after no issues, the transmission can start to act up in the ways that have been talked about? Or do these issues pretty much make themselves known from the get go?
I'm worried that with all the extra power I'm throwing at this car, that the transmission might not like it down the line...
I also have the somewhat rough shifts around gear 1-3 but it's not terrible. About the same as in other cars I know of, like a few BMW. And it's worse when engine is still at low temperatures.
And, it only manifests at normal operating temperatures, never cold.
I concur that my rough 2nd shifts occurred only when the transmission was fully warmed up...and at low speeds...like when traveling in bumper to bumper traffic.
As for how my transmission is shifting lately, still no problems so far. I do want to mention though since my car was in the shop for this issue, I have not had it in "ECO" mode at all because I was afraid the rough 2nd shift would come back since the car was still in "learning" mode after the reset.
When I first took delivery of my C450, I would put it in "ECO" mode everyday I was on the highway, then shortly after I started experiencing the rough 2nd shifts. I have no proof that "ECO" mode may be the issue her, but I didn't want to take any chances while the car was still in learning mode. My C450 is shifting like a champ now, and I want it to stay that way!
If you got the latest patch, it should shift faster and smoother in all modes, at any throttle setting.
@mass, how many miles have you put on it since the patch?
The dealership hooked up their scanning device to the car, said they found no faults, and discovered no updates for the transmission or engine management system for my VIN #...but they did perform a "Adaptive" reset and carried out an "Adaptive Drive". As for mileage, I've put on about 1,000 miles since the reset.
Did your tach ballistics change?
I would say no...shift points seem to be at the same RPMs.
10-26-2016, 11:14 AM
