722.9 hesitating between 2nd and 3rd

[axelvic]

I have an 07 E280 CDI with 7g Tronic. It’s my first Mercedes with this transmission although I’ve had a large number of cars with 722.6, which I’ve always liked. Mind you, I’ve had to replace the circuit board a couple of times which is fairly easy and not too expensive. This one though hesitates before engaging 3rd (first gear change when driving in comfort mode), letting the revs go up to a bit over the 2.000 mark before engaging again. I’ve just had the transmission fluid and filter replaced by a workshop since I don’t have the pump needed to fill the transmission. The car has done 160.000 miles and according to the service records it’s had it fluid replaced when it should previously. Is there anyone who has had a similar problem?

Regards,
Axel

 

[Baldbloke]

I have an 07 E280 CDI with 7g Tronic. It’s my first Mercedes with this transmission although I’ve had a large number of cars with 722.6, which I’ve always liked. Mind you, I’ve had to replace the circuit board a couple of times which is fairly easy and not too expensive. This one though hesitates before engaging 3rd (first gear change when driving in comfort mode), letting the revs go up to a bit over the 2.000 mark before engaging again. I’ve just had the transmission fluid and filter replaced by a workshop since I don’t have the pump needed to fill the transmission. The car has done 160.000 miles and according to the service records it’s had it fluid replaced when it should previously. Is there anyone who has had a similar problem?

Regards,
Axel

Hi Axel, I had something similar which hasn’t reappeared since the auto box flush and change. I thought it was related to fuel or turbo, but now suspect it was due to the leaking box and missing fluid.
My car is a 2007 320 CDI E class Wagon


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[milleplod]

My '56 plate E280CDi does exactly the same thing, but only until the engine's fully warmed up. I had the box done at B.J. Mason in Sheffield a month or so ago - funnily enough, it didn't do it prior to the autobox service (although the changes at low speed were a bit lumpy, which the service did sort out). I got back to Barry to query the new symptom, he said not to worry about it if it was mainly happening on a cold/not fully warmed up engine.

Pete

 

[Baldbloke]

My '56 plate E280CDi does exactly the same thing, but only until the engine's fully warmed up. I had the box done at B.J. Mason in Sheffield a month or so ago - funnily enough, it didn't do it prior to the autobox service (although the changes at low speed were a bit lumpy, which the service did sort out). I got back to Barry to query the new symptom, he said not to worry about it if it was mainly happening on a cold/not fully warmed up engine.

Pete

The hestitation on mine was only apparent until the car came up to heat too. Only happened when cold. Larger throttle openings made the hesitation more pronounced. Renewing the auto box fluid and filter appears to have sorted it.


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[axelvic]

Your symptoms sound just like mine, it's more pronounced when cold, so possibly the fluid level is a bit low, and gets better as the gearbox warms up. I'm not to happy with the garage that did the fluid change so I might have to do it myself instead.

 

[Baldbloke]

Your symptoms sound just like mine, it's more pronounced when cold, so possibly the fluid level is a bit low, and gets better as the gearbox warms up. I'm not to happy with the garage that did the fluid change so I might have to do it myself instead.

There’s a thread on here somewhere. I put some links up for some inexpensive tools and someone’s good video from YouTube [emoji1303]


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[axelvic]

Thanks a lot for the advice. There is also a slight ‘whining’ noise following the engine rpm. It sounds a bit like a power steering pump being low on fluid, but it seems to be alright. Have you experienced that as well, Badbloke and Pete?

 

[milleplod]

Thanks a lot for the advice. There is also a slight ‘whining’ noise following the engine rpm. It sounds a bit like a power steering pump being low on fluid, but it seems to be alright. Have you experienced that as well, Badbloke and Pete?

Nothing like a whine on mine.....the odd whirring noise, to be expected with all that gubbuns going round and round I suppose! Alternator bearing perhaps?

Pete

 

[axelvic]

Yes, sounds plausible. Thanks!

 

[Baldbloke]

Thanks a lot for the advice. There is also a slight ‘whining’ noise following the engine rpm. It sounds a bit like a power steering pump being low on fluid, but it seems to be alright. Have you experienced that as well, Badbloke and Pete?

No, mines quiet at the moment too. The suggestion of an alternator bearing is quite possible


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[Scottieaye]

I've owned a number of Mercedes and currently use a 2006 280 cdiestate to tow my caravan. I started having occasional problems roughly every 1200 miles. The gearbox would not change up. I would just switch the engine off and on and it would be ok for the next 1000 miles or so. Obviously I was concerned about the situation as I was due to drive on holiday to the Algarve in Portugal from my home in Scotland. I emailed 2 main dealers in Scitland, one in Edinburgh and one in Dundee. Neither bothered to answer. I took the car along to an independent Merc specialist with the Star diagnostics and he said the car needs a new electronics plate. But the plate gas to come from Mercedes via Germany. I contacted another specialist on route to Portugal and he again diagnosed exactly the same thing costing me yet more money. I decided, stupidly, to continue my holiday. I caught the boat from Plymouth to Santander the successfully towed my car so the way to the Algarve and I might add back through Spain, France and Holland and England to Scitland. On arrival back home we went to do shopping and bang.....the gearbox went and would not change gear. To cut a long story short I found an Autinatic Gearbix specialist who changed the following speed sensors on the Ekectronics Control Plate,
Output Speed Sensor
Internal Speed Sensor
After a few days same thing would not change gear
Give the guy his due he opened it up again and changed the Turbine Speed Sensor on the Electronics Control Plate. And so far it's been fine.
These sensors can be bought on line together with the removal too quite cheaply. There is also a video online showing the process to change the sensors.
Because it's just sensors bring changed there is no need for any programming.
I hope this helps somebody out there as it really is a nightmare scenario from the Stealers and unscrupulous indi's. It took the Automatic Gearbox Soecialist about 4 hours. Done.