7g Auto box needs replacing? help please!

[traffic0703]

Sorry to start a new thread off but the title of my existing one is wrong for this new development.

My car has been having gear selection issues and dealer tells me new box needed!

It would not change down using the throttle particularly if driving at a steady constant (which is the latest symptom.) If you accelerate from a constant speed the engine labours and it will not change down. It drives fine on paddles and it also drives fine if you stop - ie it takes 1st gear and then changes up through the gears no problem. Sometimes it will not take reverse when 1st started but if you go forward a little it then comes back to normal. Other than that, the box has no bad noises and is totally smooth running. It has recently gone a few weeks with no symptoms at all but the latest one of no down changes when accelerating did not seem to want to go away on ignition re set but only drove it a few times before dealer took it.

STAR shows code 0722 no output sensor signal available on the gearbox. This is a stored fault only. It has had a few checks by the dealer and mobilo.

STAR shows code can be erased and ignored.

Mercedes main dealer replaced electroplate 1 year ago so under warranty still. The car is with them at the moment with the intention of changing this under the warranty however:

They have examined the gearbox internally and tell me that there is excess play in one of the shafts which has the pickup on it causing the intermittent problem of no signal.

They tell me they now cannot do the electroplate under warranty as this is not the issue and it needs a new gearbox which writes the car off as not economic.

Full main dealer history on this car all up to date. Car has done 102,000 miles and gearbox oil changed by dealer at 37K and 95K when electroplate changed.

Has anyone come across this before? It is devastating news as the car has had a fortune spent on it keeping it exactly as it should be. I have no idea what to do from here.

 

[alexanderfoti]

Does seem to me that the electroplate has failed again, rather than the box?

 

[Craiglxviii]

Bearing in mind that the transmission has about 400 parts in it, a blanket "transmission failed ==> replace transmission" statement is really rather ignoring the root cause.

I'm with Alex, this wouldn't be the first time a replacement electroplate has failed shortly after installation.

OP, where are you? I would very strongly suggest you go to a respected Indy and not main dealer if you want high quality work done in your best interest.

 

[traffic0703]

I am near Sheffield - but to get the electroplate done free of charge, I need to use a main dealer?

I am going to get them to show me the excess play in the gearbox so I have seen it myself.

If there is play there, could it do this?

 

[KennyN]

From your first post i would expect to go to the garage and see the GB in bits as it would be the only way to "check the gearbox internally" , if you go and the gearbox is still in the car then they must employ some pretty small technicians that can root around the inside of the gearbox without dismantling it .

As mentioned , it maybe time to seek a new garage.

The fact that the box works fine with the paddles tells me that the mechanics are OK.

Kenny

 

[traffic0703]

I have seen a video now.
It is the main shaft we are talking about.
Should there be slight movement in it or should it be rock solid?

 

[alexanderfoti]

I have seen a video now.
It is the main shaft we are talking about.
Should there be slight movement in it or should it be rock solid?

Without the engine running and the car in gear, there will be play in the output shaft. To show you play on the input shaft they would have to remove the gearbox from the engine.

A worn gearbox would make noises and slip, which would log an impermissible transmission ratio code and transmission slipping codes!

 

[flowrider]

Sounds like you need a second opinion from a different dealer.

 

[traffic0703]

Have been to see the car which is on the ramps with gearbox still fitted. Sump and electro plate is off.
Shaft being moved slightly by hand through an inspection hole. I believe it is the output shaft and is at the rear end of the box furthest away from engine. I do not know if all of them will move slightly in this scenario or not.

They did tell me they believe this movement in the shaft to be causing the loss of output signal to the plate.

After discussing with manager, they are going to replace the electroplate free of charge and see what happens. I explained the other symptoms re getting warnings to release park brake on dash when engine not even on and we think a faulty output sensor may be providing false readings to other systems of the car.

 

[Botus]

why did you start a new thread !

I would change the electroplate and I expect quite a few issues to go away

however need to remember you have 4 bits that just die. The ISM, Electroplate (speed sensor), TC (torque converter lock-up clutch) and the Electronic Handbrake which has a count down timer inside and disables itself after x uses. (This can be reset in software by clever "experts")


so the issues you currently have could well be these two as well as the speed sensor,
the park brake issue as above is a designed to fail unit in itself !!! but may be its the other standard gearbox fault with the electronic shift mechanism that's designed to fail around this age (the ISM)

http://softelectronic.com/item/Merc...GENT+SERVO+MODULE++:+A+164+446+07+10,-94.html

 

[alexanderfoti]

W204 has a standard shift selector, no ISM like the 221.

 

[John Laidlaw]

204?

 

[alexanderfoti]

IGnore my crazy ramblings. I thought we where talking about a C class for some reason!

 

[traffic0703]

Yes I have had to replace the ISM last summer soon after the initial electro plate!

 

[Submariner1]

So did the electroplate fix some of the issues?
Personally If it does not, I would definitely drive from Sheffield down to see Phil at Welwyn Mercs (140 miles ?? ) before I wrote off a 2006 S Class ... assuming the body is OK.

But then I dont know your circumstances.

They are very good with gearboxes and Mercs
You should call him.

Nice people too.

 

[traffic0703]

Hi,
It has not been fitted yet, part on way from Germany. Thanks for your help.
I will post back once done.

The main symptom I was concerned about was the fact the box would not change down if you were driving on a flat road at a constant speed and you accelerated.

Only fault code being 0722 output signal - if it were other more expensive faults such as valve body, torque converter etc, would you expect other fault codes? The code I have only seems to come up as a stored fault as well but car seemed to be stuck in this condition.

 

[Botus]

when you clear codes, they come back as "stored" if its seen it again three times in a row, then it remembers it till its cleared out again even if the issue is resolved and the car is working normally.

when the electroplate is faulty the diagnostics may not work fully I think that's why you can get various codes, if somethings lost the plot it may not be able to feedback the data it should.

when my omega ABS broke all I got was can't communication with control unit. And all that was, was the paper clip rewire job you can do yourself for the price of 5mm of solder, 3p of electricity and a paper clip or £2000 at a main dealer.

if it doesn't kick down has anyone checked the switch for this is working, no idea but can imagine this may not come up in diagnostics as it could just think now ones trying to actuate it

TC would throw a code



P0703 Torque Converter/Brake Switch B Circuit Malfunction
P0704 Clutch Switch Input Circuit Malfunction
P0715 Input/Turbine Speed Sensor Circuit Malfunction
P0716 Input/Turbine Speed Sensor Circuit Range/Performance
P0717 Input/Turbine Speed Sensor Circuit No Signal
P0718 Input/Turbine Speed Sensor Circuit Intermittent
P0719 Torque Converter/Brake Switch B Circuit Low
P0720 Output Speed Sensor Circuit Malfunction
P0721 Output Speed Sensor Range/Performance
P0722 Output Speed Sensor No Signal
P0723 Output Speed Sensor Intermittent
P0724 Torque Converter/Brake Switch B Circuit High
P0725 Engine Speed input Circuit Malfunction
P0726 Engine Speed Input Circuit Range/Performance
P0727 Engine Speed Input Circuit No Signal
P0728 Engine Speed Input Circuit Intermittent
P0730 Incorrect Gear Ratio
P0736 Reverse incorrect gear ratio
P0740 Torque Converter Clutch Circuit Malfuction
P0741 Torque Converter Clutch Circuit Performance or Stuck Off
P0742 Torque Converter Clutch Circuit Stuck On
P0743 Torque Converter Clutch Circuit Electrical
P0744 Torque Converter Clutch Circuit Intermittent

 

[Botus]

on the repair last year and issue you have now, it wouldn't surprise me if the mechanic put on an old one that was just starting to play up and took the brand new original you bought an put it on a homer

 

[traffic0703]

When the car was on STAR on the driveway, they showed me that the gearbox oil temp was reading as minus 30 degrees! I assume this reading comes from the electroplate?

Does the output speed sensor feed other control modules or is it just for the gearbox control unit?

 

[traffic0703]

Update on this issue.

New electroplate fitted but would not code to car. New valve body fitted which Mercedes have covered as needed to be changed as a consequence of the new electroplate. Gearbox software updated to latest version. (last year when electroplate fitted there was no need to change valve body, it coded fine apparently)

Car was tested by dealer yesterday and put on Star twice and all good. Car driving well and no codes for gearbox showing. They did about 40 miles of mixed roads so a good test drive.

BUT I have driven car home and I am getting very nasty jolts as car slows to a halt. It has never done this before. Sometimes one bad jolt as it changes to first and sometimes two jolts one after the other. (engine hot).

Dealer is going to collect car and have it back for further inspection.

What could have happened now??