C240 new to Mercedes

[Dangerousdean]

Just bought a merc c240 OMG it has issues! Joined here to see if I can get help as I love a challenge! Gearbox is my biggest worry 722.6 bought dipstick as car was limping, stuck in 2nd, nothing was measured when warmed up, put 1ltr in still nothing! Got new plug for underneath not fitted yet, how much oil do I put in when it just reads at the bottom?

 

[classiccarzone]

You will not get very far if you do not get the codes read. Also you need to check the level properly.
Wasting your time otherwise. Is the pilot bushing leaking? has the transmission fluid travelled up the wires to the TCU?

If the limp mode is due to a transmission fault, in many cases, you will need diagnostics to clear the code before it will come out of limp mode.

 

[alecmascot]

Just bought a merc c240 OMG it has issues! Joined here to see if I can get help as I love a challenge! Gearbox is my biggest worry 722.6 bought dipstick as car was limping, stuck in 2nd, nothing was measured when warmed up, put 1ltr in still nothing! Got new plug for underneath not fitted yet, how much oil do I put in when it just reads at the bottom?

Be careful if there are two dipstick tubes, one for the engine and one for the gearbox.
It would not be the first time......

 

[AltonAnt]

The gearbox holds approx. 7lts but some of this is in the torque converter so a regular drain and refill will take 4ltrs.
You really need to get the codes read as you could just be wasting your time if it is more than low fluid and where has the fluid gone?
When maintained though these 722.6 gearboxes are pretty reliable.

 

[Dangerousdean]

You will not get very far if you do not get the codes read. Also you need to check the level properly.
Wasting your time otherwise. Is the pilot bushing leaking? has the transmission fluid travelled up the wires to the TCU?

If the limp mode is due to a transmission fault, in many cases, you will need diagnostics to clear the code before it will come out of limp mode.

 

[Dangerousdean]

It comes out of limp mode if I turn it off and on again and I checked the level through the tamperproof plug hole rather than the filling tube, it doesn’t do it all the time I’m thinking it was generally low on oil and maybe when I get time to get underneath I’ll find a leak somewhere I am hoping it will be from the plug in controller, I will continue to top up the level bit by bit until it reads something

 

[AltonAnt]

I have a code reader if you need help and I'm fairly close.

 

[DSM10000]

It comes out of limp mode if I turn it off and on again and I checked the level through the tamperproof plug hole rather than the filling tube, it doesn’t do it all the time I’m thinking it was generally low on oil and maybe when I get time to get underneath I’ll find a leak somewhere I am hoping it will be from the plug in controller, I will continue to top up the level bit by bit until it reads something

If able then drop the sump , drain the ATF , change the filter and Pilot bush (electrical connector) and re-fill. From memory these gearboxes need the level checked at 80 Deg C. Do not overfill!

See here for a detailed instruction on this :HOW TO: change the automatic gerbox oil and flush on a 722.6 'box

 

[classiccarzone]

It comes out of limp mode if I turn it off and on again and I checked the level through the tamperproof plug hole rather than the filling tube, it doesn’t do it all the time I’m thinking it was generally low on oil and maybe when I get time to get underneath I’ll find a leak somewhere I am hoping it will be from the plug in controller, I will continue to top up the level bit by bit until it reads something

Is this really due to low fluid? you do not know if you have not checked it properly.

The fluid needs to be at 80c, the car needs to be running and the next part has had some debate, move the selector through reverse and drive: in the interest of safety put it in park or neutral (though I believe it should be in drive) and you will get an accurate enough reading.

A friend had a C class with the same gearbox. That box was so low on fluid that when he changed from reverse to drive it took over a minute for it to pick up on the drive, but it never went into limp mode. It did lose the drive several times though.

The danger with having a very low fluid level is that the conductor plate can crack from the heat.

If you are replacing the pilot bushing I think you should also replace the filter and the fluid.
five litres should do you if you are not draining the torque convertor.
...but you do need to have the codes read before you open it up.

 

[BTB 500]

Conductor plate will give those symptoms (intermittent limp mode that clears after turning off and on again), and is probably the most common issue with this gearbox. But as mentioned first priority should be to get the codes checked.

 

[mbciho]

Hi and welcome dude!

 

[Dangerousdean]

If able then drop the sump , drain the ATF , change the filter and Pilot bush (electrical connector) and re-fill. From memory these gearboxes need the level checked at 80 Deg C. Do not overfill!

See here for a detailed instruction on this :HOW TO: change the automatic gerbox oil and flush on a 722.6 'box

So I’ve put another 2ltrs of oil in that’s 3 in total now and the gearbox was lovely on a test drive an hour later it got stuck in 1st until turned off so this week it’s being drained and new filter and oil and plug in adapter fingers crossed it’s ok as I need to drive it at the weekend

 

[Dangerousdean]

And even after putting 3 ltrs in still nothing on the dipstick

 

[brucemillar]

As said earlier:

Great care needs to be taken that you are indeed filling the gearbox via the gearbox tube? Next to the gearbox tube sits the engine fill tube!!! It is certainly not unknown for these to be confused.

Once you are confident you filled via the correct tube?

* Get the car on perfectly level ground (nearly level is not good enough).

*Run the car for twenty minutes or until temp is around 80c

* With the engine running!! Cycle gears through each one, including Neutral.

* With engine still running dip the box. Assuming that you have bought the correct dip-stick [emoji48]

Once you have done this? You have established the levels correctly.

!!!! Two litres is a fair chunk to add without noticing a puddle under the car. It also assumes that the car was duff when you got it?



Sent from my iPhone using Tapatalk

 

[Dangerousdean]

As said earlier:

Great care needs to be taken that you are indeed filling the gearbox via the gearbox tube? Next to the gearbox tube sits the engine fill tube!!! It is certainly not unknown for these to be confused.

Once you are confident you filled via the correct tube?

* Get the car on perfectly level ground (nearly level is not good enough).

*Run the car for twenty minutes or until temp is around 80c

* With the engine running!! Cycle gears through each one, including Neutral.

* With engine still running dip the box. Assuming that you have bought the correct dip-stick [emoji48]

Once you have done this? You have established the levels correctly.

!!!! Two litres is a fair chunk to add without noticing a puddle under the car. It also assumes that the car was duff when you got it?



Sent from my iPhone using Tapatalk

It was a cheapy. Now I’m worried when you say there is the engine filling tube next to the gearbox tube I’ve been putting oil into the tube next to the gearbox tube with the red locking clip I’m gonna take a picture

 

[Dangerousdean]

It was a cheapy. Now I’m worried when you say there is the engine filling tube next to the gearbox tube I’ve been putting oil into the tube next to the gearbox tube with the red locking clip I’m gonna take a picture

 

[Dangerousdean]

I’ve filled the wrong tube

 

[AltonAnt]

I’ve filled the wrong tube

Username matches.
Just have to drain and refill.

 

[Dangerousdean]

I’m gonna drop the engine oil and change the filter as it’s now got 3 ltrs atf in it and do the filter and oil in the box on Friday

 

[DSM10000]

I’ve filled the wrong tube

But you said earlier you put some more gearbox oil in again and it drove well for a time?

What is the il level in the engine sump showing? Surely if you have overfilled that then there would be an overfill warning? Do you know how to check the engine oil level via the instrument cluster?