W204 C250 CDi Transmission

[nealsmith81]

Hi all,
My 2011 C250 CDi Bluefficiency Sport had the stalling on cold start issue (mentioned in other threads on here). I've had the gearbox and torque converter rebuilt and this has fixed the issue.
However, the transmission is now doing a couple of things it didn't do before (I bought the car 2nd hand about 6 years ago so it could be that it should have been doing these without me realising). The transmission is 722.6.

1. Sometimes when you lift off the accelerator the revs drop to idle and the car coasts, as if the torque converter has disengaged (this seems to be at speeds <30 but occasionally has been at higher speeds).
2. When you press the accelerator a bit harder to speed up there seems to be a difference between engine revs and speed of the car, i.e. the revs rise and then the car starts to accelerate. When you let go of the accelerator the revs drop back. As if the transmission is slipping?

This is all in E (economy) mode. the manual doesn't say that the above should happen but I've read in a couple of webpages that the coasting could be an fuel efficiency thing?
Like I say, maybe it's supposed to do this but it wasn't before I had the gearbox rebuilt.
Worth saying I took it to a reputable transmission specialist to have the work done! I just want to make sure the car is behaving as it's supposed to before I go back and speak to them!

Thanks all!

Neal

 

[Tonygw]

Mm difficult to tell from your description but it could be perfectly normal. The economy mode does tend to hunt around the gears a little or stick in a higher gear when you were not expecting it to.

I tend to drive with mine in sport mode as it doesn't always look for the higher gears to achieve better mph but is much more drivable I find. The E mode can be a little annoying sometimes as I find it hunts around the gears trying to fine the best for the fuel economy, where as sport mode it tends to stay in the right gear for longer so when you need to accelerate its ready. I don't drive around like a loon but also dont hang about. I like the car to be ready if I need to go and in sport mode it always is.

 

[nealsmith81]

Thanks Tony. Anyone else with a blueeficiency who can say for sure??

Neal

 

[CarFan79]

What you are describing is pretty much how mine behaves too although I have 2013 W204 C220.