2006 7G Occasional Shift issue & Software updates

[NitJay]

Hi,

My 320cdi has the 7G gearbox, has done 78K with gearbox oil change last year.

It seems fine, other than if it's been driven, then left for an hour or so, then driven again - if I give it any more than 1/2 throttle (e.g. pulling out or overtaking) it will struggle to shift from I believe 3-4th. It will feel like the ESP has kicked in, then if I throttle off and on again it will change fine.

It's a really specific scenario, but I take it to be when the engine is warm (never give more than 1/2 throttle if it's less than optimal temp) but the gearbox oil is cool.

Is the gearbox on the way out? I've had it checked including STAR - no fault codes.

My other question is, it's an early box and I doubt it's ever had software updates. Would it be worth getting them done? I've read some horror stories post update and my indy says it's better to leave it unless there are issues.

Any advice appreciated, I'm just concerned it's going to leave me stranded at some point.

 

[PobodY]

I'd guess it's the valve body / conductor plate (is that what it's called?). - It's a known problem.

Mercedes will want to replace both parts because the come as a set, but you can have them repaired if you send them away... or so I'm led to believe from this forum.

 

[zipdip]

Yes you can get the speed plate repaired,get the car on a Star and see if there are any codes,hopefully there will one at least that will point to a particular valve ,if there are no codes,it is still best to get it serviced by a repairer,for some reason there is not always a fault recorded in the ECU,cost can vary a lot a couple of years ago people sent the speed plate to Bulgaria,Mercedes will look for around £1500 to replace the speed plate,if you have a mechanic who will remove it from your car ring 01773535638 they will repair your speed plate for around £300 the beauty of having it repaired is that it will not need pairing with your ECU that a new one would at extra cost on a star

 

[NitJay]

Thanks guys, so it's definitely a fault and not just a bit of a poor unit. Will it break down at all?

any experience with the software updates out of interest? Do they improve the changes?

No fault codes on Star when it was checked last month.

 

[Codger49]

Your scenario is not quite in line with the electroplate failure that I experienced at 68k miles on my CLK in 2015.

Mine was the classic symptom of the gearbox refusing to change up until car had been stopped and ignition switched off and on, it would then drive normally. Lifting off accelerator had no effect. Mine did show a stored code though, "P2767 The signal from component Y3L8n2 (Internal speed sensor (VGS)) is not available".

Apparently, repeating this ignition cycling can keep it going for months, but some day in the future it will go hard and you will need a flatbed lift to recover the car.

The cure was a new electroplate from MB, which required coding to the car as it is a "theft related part". Total cost, at an experienced indy, was £700.

Included in the repair was an update of the gearbox software, this has made changes very smooth, indeed almost imperceptible.

I note yours is a cdi, I am sure I have read posts on this forum decribing hesitant gearbox changes that turned out to be issues with the air and fuelling arrangements for the diesel engine. I have never had a diesel, so I can only recommend you take your car to an experienced indy (e.g. Wayne Gates in Harrow or PCS in Hordean) for a thorough check.

 

[NitJay]

Hmm, this is interesting Codger49 I did a search based on your info and found this thread.
https://mbworld.org/forums/e-class-w211/455444-help-e320-jerking-during-acceleration.html

In here the guys are saying it's most likely turbo or fuel filter. I don't want to shell out for a turbo and then it actually be the gearbox or vice Versa.

 

[Codger49]

Hence the recommendation to visit an experienced indy to avoid the rather expensive trial and error parts replacement approach that many others seem to have adopted.

Don't know where you are located, but if you post up your location, members here are likely to recommend indys within reach.

Two of your symptoms made me think of the engine; occurs on acceleration, but ceases on lift off; and no codes - 7G gearboxes are pretty well monitored, plate type issues usually have one or more fault codes.

 

[NitJay]

Sure, I'm in Mid Sussex!

 

[Codger49]

Talk to Olly at PCS in Hordean then (he's BlackC55 on here). PCS are very highly regarded by forum members.

Steve Garlick at Stevensons Independent Mercedes Specialists in Mereworth between Tonbridge and Maidstone also knows his onions. He was a MB Diagnostic Technician until a couple of years ago when some forum members encouraged him to start up on his own. Has a reputation for tracking down faults that others can't find.

PS Wayne Gates in Harrow aren't that far away either. Also very highly regarded by forum members.

 

[zipdip]

Well guys if you read the link that Nitjay posted this morning you will see that it comes back to the telephone number I gave earlier,they can repair your speed plate cheaply they also do ECU's for turbos',there is nothing wrong with going to PCS top people but they will get the plate repaired and if it is the ECU on the turbo likewise,many owners of the 320cdi get these problems they happen occasionally and we get to work out how to get round them,there are no faults recorded,it comes down to spending what is a small amount to fix the speed plate and see if that fixes the problem and then maybe getting the turbo ECU sorted if the speedplate repair does not fix the problem.

 

[NitJay]

Thanks all, I'll get in touch with the guys mentioned.

Much appreciated - will report back once I have a solution.