Automatic not changing gears properly

[astorz]

E320cdi 2003 I am finding the automatic gearbox is choosing the wrong gear especially when I have slowed down and start to gather speed. It seems it is still struggling in 4th gear, shuddering - I have resorted to changing gears manually - took it to a Merc diagnostic - they said nothing showed up on computer. Any ideas?

 

[Alex Crow]

Is it possible that it is actually changing gears fine, and at the right time, but just shuddering a lot?
In other words, have you confirmed by the rev counter that your assumption is correct?

I only ask because shuddering is very common (from eg TC) on this car, and will not log fault codes.

 

[television]

Do you have any humming or droning when pulling lightly in top at RPM between 1400 and 2500

 

[astorz]

Rev counter is fine, and yes there is shuddering. Thats what makes me think it is staring in 4th when it should actually be 1st then moving upto 2nd.
No humming or droning.

 

[astorz]

I suppose it could be that the gearbox oil needs changing or the valve block needs adjusting - but I do have it regualryly serviced and would have thought that would have been checked - though not by an authorised Merc dealer - but someone who knows about Merc

 

[television]

I suppose it could be that the gearbox oil needs changing or the valve block needs adjusting - but I do have it regualryly serviced and would have thought that would have been checked - though not by an authorised Merc dealer - but someone who knows about Merc

40k miles is the normal time to change the fluid, most comment on the smoother changes

 

[Alex Crow]

Rev counter is fine.

I rather meant for you to confirm the assumption that it is in a certain (wrong) gear, by rpm/speed comparison.

 

[astorz]

Well the rev counter is saying 10 and I am going along at 20mph and the car is shuddering it the changes down if I apply a little acceleration or if infactvi come to a complete stop and move off / it seems to think it is still in 4th, when I click over to manual it is in fact in 4th

 

[Naraic]

Well the rev counter is saying 10 and I am going along at 20mph and the car is shuddering it the changes down if I apply a little acceleration or if infactvi come to a complete stop and move off / it seems to think it is still in 4th, when I click over to manual it is in fact in 4th

No you aren't...if I click over to manual as you say...I also display 4...doesn't mean I'm in 4th. It does mean that you will not go into 5th as you accelerate. And yes if you accelerate the car will change down...it's kick down.

 

[jprwno15]

I had this two weeks ago on my s class diesel

Get into the car and re set the adaptive transmission

1) Turn key to position 1 ie do not start the engine
2) Floor the throttle for 5 secs
3) Turn key to off position
4) wait 2 mins

THen start car and drive off. The factory settings will be restored. Worked for me, good luck

 

[ELGRINGO]

Hi as your garage or indie carried out a glycol test for cross contamination, have seen plenty with simular faults.

 

[television]

Hi as your garage or indie carried out a glycol test for cross contamination, have seen plenty with simular faults.

That was my thinking as well