Manual hard shift - Comfort, Sport, Sport plus - TCU Tune?
Thread Starter
Junior Member
Joined: Dec 2020
Posts: 22
Likes: 2
From: Baltimore, MD
2018 C43 AMG Coupe
Manual hard shift - Comfort, Sport, Sport plus - TCU Tune?
I recently installed the EC tune stage 1 and will also install the TCU tune. From what I have heard the TCU tune helps smooth the shifts. Can anyone vouch for that? Anyway, no matter what mode I am in, when i am in manual mode every gear shift up until 5th gear usually has a hard dull bang into the the next gear. I have tried driving it like a real manual and letting off the gas as I shift then hit the gas right after the upshift connects and I have tried shifting holding the gas peddle steady. What method has worked for you? I have tried shifting gears at 3000pm and higher to find that sweet spot. The car is in such a hurry to get to that next gear and just isn't smooth. I worry that the hard bangs in shifts are eventually going to break my transmission. In Comfort mode my car tries to get to 4th gear so fast even if im at 20 mph and even that is bumpy and hard. I guess the question is, has letting off the gas between gears helped the shifts or maybe giving it more gas between gears is better. I think subconsciously I am letting off the gas in anticipation of a hard shift in my head thinking the damn car is gonna break. That may be making it worse. Its a 2018 c43 and stock other than the stage 1 tune. 2000 for a tcu tune, if it improves the shifts and increases power than it might just be worth it.
Senior Member
Joined: Jul 2020
Posts: 353
Likes: 60
C43
The car in Sport+ will try to shift hard and provide an artificial jerk for "sportiness". If you're experiencing hard jerks upshifting while in normal or comfort mode then that is a bit strange; it doesn't happen on upshifts in my 2020 C43. However, downshifts for me into 2nd and 1st gear are ALWAYS harsh for me.
With this automatic transmission, it's better to hold the gas while you're shifting. If you let go of the gas then shift, the car slows down immediately, which will naturally be jerky.
With this automatic transmission, it's better to hold the gas while you're shifting. If you let go of the gas then shift, the car slows down immediately, which will naturally be jerky.
Thread Starter
Junior Member
Joined: Dec 2020
Posts: 22
Likes: 2
From: Baltimore, MD
2018 C43 AMG Coupe
It usually does this cold or not quite 100% warmed up. But the hard bump kinda shift was at anytime in 2nd and 3rd gear. Its weird because in sport +, downshift 3rd to 2nd and 2nd to 1st is extremely smooth. Btw, my shifts have improved significantly today. Since I just did the EC stage 1 tune, I unplugged the negative wire from my battery. However, my individual mode, saved radio stations, saved seat settings and even the clock didn't get reset. I tried unlocking the doors after I unplugged the battery so the battery was def not connected. But how did my car save all my settings including the clock? Anyway, My point was to reset the ECU and hope this happened. But what I am trying to get to is this. I did what this YouTube video said to do to reset the transmission and when I drove my car today the shifts were smooth cold and warm engine. I wish I would have driven my car first after I plugged the battery back in before resetting the tranny. Now I don't know if the smooth shifts are from an ECU reset or if holding the gas done for 10 seconds then turning off the ignition for 2 minutes actually reset the tranny. But between 1.5 to 2 mins into the process I heard like a motor sound for a few seconds then went away. But the shifts are smooth and not as jerky.
Senior Member
Joined: Mar 2018
Posts: 323
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From: Central Florida
'15 C400 and '15 ML350
The trans/pedal reset is what I was going to recommend. Do not try to drive it like a manual, the ECU/TCU expects the driver to stay on the gas while the torque converter transfers the power and slips when needed on gear changes. Trying to take your foot off with a delayed drive by wire setup like this is just confusing the TCU on the amount and fill times on the shifts.
