Transmission harsh shifting
Today, 06:43 AM
#1
Junior Member
Thread Starter
Transmission harsh shifting
I have a e250 cdi 4matic 2012 WDD2122821A574817
with 370k km on it and it's transmission has sometimes harsh shifting, its similar as driving a stick and dropping the clutch pedal rather then releasing it slowly.
This is worst when the car is cold and almost stops when it has reached working temperature.
The dealership ran a diagnosis on it and serviced it, they did not find anything wrong with it, but after the service it behaved normally and shifted really well, but has started acting up again.
This happens when it shifts up and shifts down.
Anyone knows what might be troubling it?
with 370k km on it and it's transmission has sometimes harsh shifting, its similar as driving a stick and dropping the clutch pedal rather then releasing it slowly.
This is worst when the car is cold and almost stops when it has reached working temperature.
The dealership ran a diagnosis on it and serviced it, they did not find anything wrong with it, but after the service it behaved normally and shifted really well, but has started acting up again.
This happens when it shifts up and shifts down.
Anyone knows what might be troubling it?
Today, 12:18 PM
#2
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MY'14 W212 M276 3.5NA @60kMi
extra poor shifts
I have a e250 cdi 4matic 2012 WDD2122821A574817
with 370k km on it and it's transmission has sometimes harsh shifting, its similar as driving a stick and dropping the clutch pedal rather then releasing it slowly.
This is worst when the car is cold and almost stops when it has reached working temperature.
The dealership ran a diagnosis on it and serviced it, they did not find anything wrong with it, but after the service it behaved normally and shifted really well, but has started acting up again.
This happens when it shifts up and shifts down.
Anyone knows what might be troubling it?
with 370k km on it and it's transmission has sometimes harsh shifting, its similar as driving a stick and dropping the clutch pedal rather then releasing it slowly.
This is worst when the car is cold and almost stops when it has reached working temperature.
The dealership ran a diagnosis on it and serviced it, they did not find anything wrong with it, but after the service it behaved normally and shifted really well, but has started acting up again.
This happens when it shifts up and shifts down.
Anyone knows what might be troubling it?
High mileage wear of clutch friction may be an obvious cause. Old age does kill.
Standard poor shifts are caused by delayed CAN-Bus networking between ECU <---> TCU without any recorded fault.
-- Tranny is always reacting hundreds of milliseconds late after engine requests.
-- The RPM matching can hardly be coordinated.
-- The shaft rpm mismatch provide the rough shift condition.
Poorly controlled engine heat can help thin out ATF viscosity. The excellent TCU uses multiple temp tables to try adjust shifts within limits.
What is causing this on your chassis is either one hard fault or a combination of modules.
You will need to scan your chassis to read/clear disrupted modules.
The bottom line is most tranny are not guilty, don't waste money with it. It will adapt well once a normal environment is restored.
You have done the most important part getting clean ATF service. Now drive your engine easy to prevent wasting old clutch frictions with hot sloppy shifts.
+++ Adaptations hardly help.
A running TCU learns adaptations really well all by itself but has limits to what be hidden. It uses historical averages from the best German computations.
The issue here is not about valvebody executing the gear shift poorly... it is about receiving late requests.
Totally external and independent of TCU banging gears.
++++ Added header to RECAP condition
high wear (+ timings)
Last edited by CaliBenzDriver; Today at 03:19 PM.
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