W168 Auto Gearbox - Please Please Help

[Pyro]

Please can someone help.

I have just recently had a automatic gearbox fitted by a garage, the gearbox came with a warranty and worked fine at first.

But after a while I noticed when I went around a sharp bend the engine would race and lose some power to the road.

I thought that the transmission oil had not been filled correctly, and checked underneath for any signs of leakage, there was none!

I topped up with 1 litre of transmission oil and the problem went away for a short time.... when driving down the motorway a couple of weeks later I noticed the engine would race between third and fourth gear, easing off the throttle it dropped into fourth fine.

Then once after a longer drive the car slipped into fault mode and now only drives in reverse.
I took it into the garage and who drained the oil and measured 1 litre only, they then refilled to the recommended ammount and still no forward gears.

Where can all this oil of gone? If no signs of it outside the box, and what is likely to be wrong?

PLEASE PLEASE HELP THE GARAGE IS TAKING THE MICHAEL!

 

[ALFIEBEARD]

Autobox losing oil?

Hi I know very little about the type of box fitted to your Mercedes, but I once had a very similar experience with my old Rolls Silver Spirit, and we eventually found out that there was a vacuum pipe from the intake manifold to the autobox, and this pipe had a diaphram valve in it (I think it was to do with the kickdown) and the valve had failed and basically the engine was sucking the oil out of the box and burning it, do you have any smoke on the overun, this is just a thought as no doubt your gearbox is nothing like the GM300 that was fitted to my car but it is food for thought.
Alfie B

 

[Pyro]

I don't think there is a vacuum pipe like what you say. But thanks, I am still non the wiser.

 

[television]

Hopefully SAM will see the post in the morning,he knows the A well

 

[Pyro]

These A classes were not fitted with a dip stick, is it possible it was thrown up and out of there and I have not noticed, I always park in the same place and there is no red oil on the road.

 

[television]

Dip stick are no longer fitted to any MB, only the tube with a cap on top

 

[meanie]

First thought is that it's going into the cooling system through the heat exchanger,but I'd have thought that they would have picked up on that.

Your biggest problem could be exercising the warranty if this is the case.

 

[Pyro]

you would have hoped they would, but when refilled why no drive? Has a valve seal likely gone?

 

[Cole@MBS]

Hopefully SAM will see the post in the morning,he knows the A well

That might be the case Malc but this one has me stumped!!

The box is sealed as far as im aware and fully electronic!

Maybe JIB has some more ideas, hes pretty good with these boxes! the oil has gone somewhere!

 

[Pyro]

I expect the oil has come out of the dip stick, there was no bung refitted in it!
Strange I did not see any under bonnet or on floor.

The main problem is :

Why no forward drive only reverse?
And how much is it likely to cost to fix?

Any help would be appreciated.

 

[jibcl500]

These auto boxes take about 8 litres of oil!!! if its been dipstick checked (engine running and at temp) and its showing as ok then the gearbox oil level sensor must be at fault, how many miles had the replacement box done?

These autos typically fail at 50-55 thousand miles.

Has the been put on diagnostics ?

Sounds like box needs adaptation erase to delete all stored settings.
jib

 

[Pyro]

The garage tells me the diagnostics says a valve needs replacing that can be done by removing the oil pan........

still no indication of where the oil has gone, but apparently the pressure in the cooling system is higher than in the gearbox thus water would go into the transmission rather than oil into the coolent.

Don't know whether it will fix it, but will keep posting!

 

[Pyro]

The saga continues

Please help anybody!

It appears the valve body has three valves in it, and one of these has gone!

Mercedes doe a complete valve body but it comes with an electrics pack, however there is a valve listed seperately but they are not sure whether it is the correct part.

Does anyone know whether the valve can be ordered on its own, and if so what would be the part number?

Regards

Tony

 

[jibcl500]

Shifter valve MA168 377 01 35 £28.00 roughly, there will be other valves in the valve chest, these select 1,2,3,4 etc etc, the shifter valve and all other valves have had several part number changes, the valve chest can be removed once the sump is off, the micro filter will fall out as will half a litre of oil.

More likely the ECU is faulty, lets face it it sits in all that oil !!!!! ECU test is about £300 + vat but if its beyond repair then £1060 + vat from Mercedes as its coded to the chassis number to your car.

Rough estimate £1500, is your car worth £1500?

jib

 

[Pyro]

Thankyou for the part number

Thanks for the info. Greatly appreciated.......

The forward gears are the ones that have gone.
Is this the shifter valve?

Or one of the other valves.
I am told the ECU test is fine, just the valve thats gone.

The scematic I have is labelled Y37y4 I will post an image can anyone confirm the valve is the right one?

 

[jibcl500]

Yes number sounds right, shifter valve is the most common problem but it doesnt always fix the fault.

I assume its full automatic, if the car is ticking over with no F on the display running the shifter through the box should bring up F on the display if so then the shifter valve is at fault. Diags adaptaion erase and new shifter plus all the otehr parts will or should keep it good for 100 miles or so then fault will come back hence ECU epair or replace.

Sorry Ive spent weeks on the A auto box and still cant see there is a logical fix other than hit a tree.

jib

 

[Pyro]

Shifter Valve

Why would the ECU need replacing after 100 miles or so?

The ECU test is clear.....



Here is link to the Auto Box, the schematic shows the valve in RED being the one at fault.

 

[Pyro]

Does anyone know where I can get the valves in the diagram above?

 

[Cole@MBS]

Try Merc parts dept!

 

[Pyro]

Hi Tried that but they are clueless in Blackburn!

The problem is that Merc Part Depot cannot tell me whether the valve I order is the same.

The say the valve body lists only one valve, then you speak to cicely commercials and they say you cannot get the valve on its own.

Talk about confusing!

One says a valve is available but cannot confirm that it is the right one.
The other says you have to get the full electrics pack that costs over 1k.

What is the correct answer?