7G Gearbox - One off problem moment

[Lit91]

Guys,

Was driving the other day (w209 2006 CLK 320CDI), and all of the sudden, the car felt really weird after a junction (huge lack of power & lots of revs on pulling out), turned out that the box has selected 5th gear & wouldn't use anything else.

The journey has also included a short motorway strip, where the car wouldn't change up or down from 5th (even in manual controls). I stopped over trying to park the car, stuck into reverse & there was no drive at all, just revving like it was in neutral.

So I've switched off the engine, gave it a couple of seconds & started it again. The car seemed fine after that, all gears present etc...

Now was this just a moment where the gearbox brain got confused & there should be nothing to worry about? or could this potentially be a sign of a problem.

The day before I was playing around with the manual mode on the road, could this be the cause?

The car has had a recent gearbox oil change, (1 month ago) at prestige car services in Horndean.

In general, I wouldn't say that the gear changes are very smooth, seemed like they were smoother prior to the oil change, but this may just be a personal perception by paying attention to the changes.

 

[rifiki]

I had similar problem only it would not chage up. Stopped at traffic lights, put in to neutral, green light into drive nothing. Switch off ignition, started and had drive and only in low gear about 15 MPH ret 1000 RPM. Landed up with a £525 repair bill.

 

[Lit91]

I had similar problem only it would not chage up. Stopped at traffic lights, put in to neutral, green light into drive nothing. Switch off ignition, started and had drive and only in low gear about 15 MPH ret 1000 RPM. Landed up with a £525 repair bill.

What was the problem?

Mine seems to be fine now, throughout all the gears - looked like the gearbox has just confused itself on that drive only, unless it was a prevention procedure because of something else.

I just keep the car in drive throughout, there was no change to neutral, then drive at the junction. Its like it stuck in 5th. Hope the gearbox oil level isn't low.

Is there a way to check?

 

[BlackC55]

I expect it will be a faulty speed sensor.

If the level was low it would not give you those symptoms. The only way to know what caused it is to plug it in and read the codes.

 

[Lit91]

I expect it will be a faulty speed sensor.

If the level was low it would not give you those symptoms. The only way to know what caused it is to plug it in and read the codes.

No doubt in your service Olly,

I trust PCS from my last visit, but just double checking the reason why this may have happened, better sort an early symptom rather than suffer a consequence, if there is one.

Checking / topping up the oil was the first thing that came to mind. But I'm sure you'd know better.

 

[rifiki]

No dip stick on 7g. Take it to indie with MB star and have the codes read, this is not a DIY auto box.

 

[logman]

Get codes read possible electro plate in box issue see post 2 £500+ to repair

 

[Lit91]

Same problem occurred again last week, this time in a different gear :/

 

[Howard]

Get the codes read.

Prepare for expenditure.

 

[Lit91]

Get the codes read.

Prepare for expenditure.

any recommendations on where to go?

 

[Howard]

any recommendations on where to go?

Olly ?

 

[Lit91]

Olly ?

Will give PCS a try, thought it had to be a gearbox specialist...

 

[Lit91]

Any thoughts if calibration / resetting the adaptation settings is worth trying? And how is it done?

 

[whitenemesis]

Only possible via STAR.

 

[Ian Topping]

I experienced same problem. Gearbox refused to change gear, so I pulled over, switched the engine off for 10 seconds or so and then started and it went ok thereafter. However I called with a garage the next day and the Star identified the speed sensor problem and quoted about £600 to fix.

 

[expandyman]

I also have just experienced an issue with my 7g on my 2005 w211 e280. After an easy drive on the m1 for 90 minutes, pulled off and noticed a lack of gear changes. Switching off solves the issue for a few moments. The gears will change up to top, but then stays there. Again from cold, the car is ok from 10 -15 minutes. Manual changes appear ok and will select the correct gear. Ie if the car is in drive and I start going up a hill, selecting manual will instantly select 4th or 5th as appropriate. Approaching a stop I have been putting the car into neutral otherwise I get a small jolt on stopping. Had the oil changed about a year ago / a few thousand miles ago.

While I understand the solution will be to take this to a garage, it was not on my plan to do this while taking a few days off in Harrogate and the surrounding area. Not sure the wife really wants a tour of local Mercedes garages. Any help, comments or advise greatly appreciated. Thanks.

 

[Lit91]

I experienced same problem. Gearbox refused to change gear, so I pulled over, switched the engine off for 10 seconds or so and then started and it went ok thereafter. However I called with a garage the next day and the Star identified the speed sensor problem and quoted about £600 to fix.

Did you get it fixed in the end?

As previously mention, mine is all back to normal now again - guessing it's having its own moments at times...

 

[N4D5]

I also have just experienced an issue with my 7g on my 2005 w211 e280. After an easy drive on the m1 for 90 minutes, pulled off and noticed a lack of gear changes. Switching off solves the issue for a few moments. The gears will change up to top, but then stays there. Again from cold, the car is ok from 10 -15 minutes. Manual changes appear ok and will select the correct gear. Ie if the car is in drive and I start going up a hill, selecting manual will instantly select 4th or 5th as appropriate. Approaching a stop I have been putting the car into neutral otherwise I get a small jolt on stopping. Had the oil changed about a year ago / a few thousand miles ago.

While I understand the solution will be to take this to a garage, it was not on my plan to do this while taking a few days off in Harrogate and the surrounding area. Not sure the wife really wants a tour of local Mercedes garages. Any help, comments or advise greatly appreciated. Thanks.

I had same problem for a while mate on my W211 e320 Sport, ended up with a bill close to £2k - i needed to change the box plate which has all the sensors on it. The box then needs to be linked to mercedes computer sytem for them to program it. My indi box specialist done the work and then got mecedes to program. I got the whole box reconditioned as i am keeping car and didnt want somehting else going wrong. I had permenant sensor problems and the turn off and on would only help for a few mins.

Get it plugged in and checked out properly before you spend anything.