2007 E320 cdi sport problem

[boxer 01]

hi whilst braking just before coming to a complete stop I have been experiencing a feeling of the car sort of lurching/jerking (not violently, in fact very smoothly) then coming to a stop, it doesn't seem to do it all the time and is more noticeable just before car comes to a complete halt. Applying brakes at high speed does not cause any problems. About 5000miles ago I had new discs and pads fitted and brakes have been perfect.
I have been spending a lot of time recently stuck in traffic crawling along for maybe an hour a day(dreaded bridge repairs) and I was wondering if this is causing an issue with the 7g adaptive gearbox. Car is otherwise very smooth and responsive, I have been following various posts relating to this type of gearbox and before I take it to a specialist I would like to hear from anyone who has got any ideas as to why I am experiencing this problem and if its a gearbox issue or something else.
regards
boxer.

 

[GordonTarling]

When did you last have the ATF changed?

 

[Tinkerer]

Perhaps you are becoming more sensitive to the gearbox changing down through the gears as you come to a stop. This can be very pronounced on some cars, certainly an A class that I test drove (no comparison made here) was very unnerving as the change into 1st at the last seconds produced a considerable jolt. If other driving conditions are smooth I would not be tempted to a knee jerk reaction.

 

[michael8554]

It's not clear from your description if the jerking is coming from the brakes or the gearbox.
If you come to a halt without using the brakes do you get the jerking?
Then gearbox to blame.
Does it only happen when braking?
Then possibly ABS pulsing, which should normally only happen during very rapid deceleration, or on wet/slippery roads.
Michael

 

[boxer 01]

Hi Gordon ATF was changed aprox. 20000 miles ago

 

[Deleted member 37751]

It sounds very much like the (in)famous 2nd gear to 1st gear 7G 'box jerk; "they all do it".

 

[boxer 01]

Hi Michael coming to a halt without using brakes car is fine, problem occurring only when braking and more noticeable just before coming to complete stop.

 

[KeithJG]

My 06 C320CDI comes to a stop smoothly (hard braking or gentle braking) without me knowing about the box dropping gears but only when i go up my steepish road to park at home when i slow up gently it will grab 1st gear noticably......but then not always!

 

[Bjm34new]

Hi Michael coming to a halt without using brakes car is fine, problem occurring only when braking and more noticeable just before coming to complete stop.

check the tyres for ovality, jack a wheel off the ground and spin the wheel by hand if a tyre is oval you will be able to see a deformation. Had the same issues with the wife's Smart, changed pads and discs still had the almost soothing rocking motion when slowing down when someone else suggested checking the tyres and there we found the problem, changed the 2 front tyres and she's now back to normal

 

[boxer 01]

Just been to Preston and back decided to test the brakes as there were no other vehicles about, whilst doing 75ish as I approached my slip road I applied brakes quite firmly, absolutely flawless until the last 10-15 yards before I got to the roundabout when the familiar stop start motion appeared. I will check the tyres tomorrow but I have a feeling that this is something to do with the brakes.
This problem is more annoying than actually affecting the cars ability to perform how it should hopefully I shall get to the root of the problem and will keep everyone informed.

 

[GordonTarling]

Lumpiness when coming to a halt seems to be a fairly common problem with the 7G gearbox. If you haven't already done so, it's worth asking your main dealer to check for gearbox software updates.

 

[guydewdney]

Snick into neutral at 40mph, try again. Might be a combination of braking making the gearshifts different.

 

[Guy.Pap]

Snick into neutral at 40mph, try again. Might be a combination of braking making the gearshifts different.

If doing this make sure you come to a complete stop before dropping back into drive

 

[boxer 01]

Snick into neutral at 40mph, try again. Might be a combination of braking making the gearshifts different.

I have never shifted into neutral whilst driving is it safe to do so ?

 

[boxer 01]

Snick into neutral at 40mph, try again. Might be a combination of braking making the gearshifts different.

whilst driving along at 30ish slipped into neutral and braked to stop and the problem seems to be still there, so it might well be the brakes maybe a warped disc, although pagid discs arent even 12 months old and no movement in pedal when applying brakes. a bit stumped relly because it feels as though the fault is sometimes there and at other times its ok.

 

[Dave JRH]

Hi Boxer,
What you describe is exactly the same "problem" as my car. I had new front discs and pads fitted about a year ago and after 6 months i started to feel a slight snatching when braking, but not all the time. i have deduced that it is warped disc related, either the new front ones or the rears requiring replacement. It doesn't happen all the time because the warps are not synchronised all the time, when they are the effect is more pronounced.
Hope this makes sense and helps
Dave

 

[boxer 01]

Hi Boxer,
What you describe is exactly the same "problem" as my car. I had new front discs and pads fitted about a year ago and after 6 months i started to feel a slight snatching when braking, but not all the time. i have deduced that it is warped disc related, either the new front ones or the rears requiring replacement. It doesn't happen all the time because the warps are not synchronised all the time, when they are the effect is more pronounced.
Hope this makes sense and helps
Dave

Thanks for that dave. The problem now is which discs are warped. I have my car booked in for an mot on wednesday so I will ask tester to check brake balance. Although I am not sure how he is going to check. From the size and thickness of the new front discs that were fitted I would be surprised if one is warped. Have you got rid of your problem dave if so how.

 

[Dave JRH]

Hi Boxer,

No i am living with it as it is such a delicate imbalance, i will look into it further once the weather warms up, i hope it is the rear discs and not the new fronts.
I shall keep you informed

Dave

 

[AkisGr]

If doing this make sure you come to a complete stop before dropping back into drive

Why is that? Can't put it into D while moving?

 

[Guy.Pap]

Yes you can move from neutral to drive whilst moving but it can cause transmission shunt as the clutch bands grab putting load on them in a direction they are not used to. Not good if you suspect a gearbox fault, does not do a a good gearbox any favours.

You would not sit at 2000 rpm in neutral and then drop it into drive would you....