C450: Gear shift jerks in sports plus mode
I really need your experties here...
Just got my new c450 for couple of months and now there's about 2K KM on it. I'm a believer of "breaking in period" and I have been very careful with the first 2K, never stepped on GAS too hard and never used sports or sports plus mode.
I switched on the sports plus mode for the first time yesterday since it's already passed 2K. When I pulled ahead at a red light (stepped on gas really hard, about 6000-7000 RPM) then let go of the gas, the car basicly jerked really bad and noticeably 4 time in a roll, and every time it jerked RPM dropped about 1000. I have tested it again and same thing happened another time. I understand when you let go of gas the computer is trying to gear up but it felt horrible.
I'm little scared right now, although everything feels normal in other modes and gear shifting does feel fine still, is this kind of jerking in sports plus mode normal?
Thank you guys.
I really need your experties here...
Just got my new c450 for couple of months and now there's about 2K KM on it. I'm a believer of "breaking in period" and I have been very careful with the first 2K, never stepped on GAS too hard and never used sports or sports plus mode.
I switched on the sports plus mode for the first time yesterday since it's already passed 2K. When I pulled ahead at a red light (stepped on gas really hard, about 6000-7000 RPM) then let go of the gas, the car basicly jerked really bad and noticeably 4 time in a roll, and every time it jerked RPM dropped about 1000. I have tested it again and same thing happened another time. I understand when you let go of gas the computer is trying to gear up but it felt horrible.
I'm little scared right now, although everything feels normal in other modes and gear shifting does feel fine still, is this kind of jerking in sports plus mode normal?
Thank you guys.
Regardless, in your scenario, I'd recommend putting it in S+ and Manual, and do the exact same thing, step on it hard and let go of throttle, see if it's still dropping the RPM by 1000, it shouldn't in this case as your essentially holding the gear. If it still does, then you should bring it up with your dealership. In your case it could be that the timing of your de-throttle was matched with the computer's timing for shifting up so it created a bigger jerk than usual.
As with what most others have said, S+ does shift harder, and you don't really need it in city driving imho.
I think the most comfortable shifting behavior for our AMG tuned tranny is actually Sport mode. I prefer the shifting range of the Comfort though. The comfort does try to slow down shift speed considerably to the point that the car jerks the opposite way if you know what I'm trying to say. I'm hoping all these will be fixed later on as the C450 gets new firmware for the tranny. Hope this helps, cheers!
Last edited by Terminator1; Feb 14, 2016 at 11:59 PM.


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This is a very similar feeling to coming off the throttle to quickly while in first gear with a manual transmission. The principal is the same, engine compression in low gear exerts more braking force upon the vehicle.
My wife and I both adapted to this instinctively. Both of us had learned on and had driven manual transmissions for years, so that throttle control is kinda hard-wired in I guess.
The fix, go smoother with the gas or switch from sport+ to sport or comfort mode.
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A sport tuned transmission would still jerk in this scenario precisely because you are holding it in 1st or 2nd gear and coming all the way off the throttle.
In a typical automatic transmission (for example my dog car/grocery getter Ford Escape) if you stomp on the gas the car revs up and quickly accelerates. If you come off the gas rapidly the car will still jerk a little but the vehicle will almost always have shifted into a higher gear as you come off the throttle. The higher gear reduces the amount of mechanical advantage of the engine braking force applied so the severity of the lurching/jerkiness is much less.
The C450 and similar type vehicles with sport tuned transmissions are designed to hold the gear upon acceleration and bounce off of redline or close to redline for the shift points. So if you are pulling of the throttle rapidly you are going to to be in a lower gear than you would be in a typical car or in the comfort mode of the C450.
This is a very similar feeling to coming off the throttle to quickly while in first gear with a manual transmission. The principal is the same, engine compression in low gear exerts more braking force upon the vehicle.
My wife and I both adapted to this instinctively. Both of us had learned on and had driven manual transmissions for years, so that throttle control is kinda hard-wired in I guess.
The fix, go smoother with the gas or switch from sport+ to sport or comfort mode.





