W210 722.6 transmission randomly works.

[Calle1]

Hello,
Just bought a MB E220 cdi with a faulty transmission.
I got it real cheap and I already counted for buying a new gearbox.

However, before ordering a heavy 722.6 with torque converter and dragging it to the workshop I thought it could be worth asking here for input if the problem might be related to the conductor plate that i read about or something else.

The problem is that the car does not always move when putting the gear lever in D or R.
When pressing the gas pedal it does not rev like if it was in N or P, it only revs a very little or not at all. No whining or other wierd noises. This happens about every second time the car is started.

It is not possible to get the car moving by putting the gear level to P/N and then back to R/D.
The only way to get the car moving again is to turn of the ignition and restart the engine.


I haven't had the opportunity to try it in higher speeds yet - also avoided it just in case the car should stop moving completely..

At first I was convinced it was a mechanical problem but the fact that the problem is Intermittent makes me think it could aso be some kind of electrical problem?

Thanks in advance.

 

[LostKiwi]

First things first smell the oil (yours will have a transmission dipstick). If it smells burnt there could be mechanical issues.
Also check colour - if its black as above - it should be a red colour.
To verify conductor plate you need to get it on STAR (nothing else will do) and get codes and live data checked.
If you decide to change the box ensure the new box is the same model as the old. There are multiple variations on the 722.6 box - its a family of boxes not just one type.

 

[Calle1]

First things first smell the oil (yours will have a transmission dipstick). If it smells burnt there could be mechanical issues.
Also check colour - if its black as above - it should be a red colour.
To verify conductor plate you need to get it on STAR (nothing else will do) and get codes and live data checked.
If you decide to change the box ensure the new box is the same model as the old. There are multiple variations on the 722.6 box - its a family of boxes not just one type.

Thanks for the reply. I'll definitely check the oil tomorrow.

Turns out that the cost towing the car to a MB workshop and then the STAR diagnosis + the cost of an OEM conductor plate will cost me almost the same as a gearbox. Already found one with the same numbers

 

[Calle1]

Update: The ATF seems to be good, red colour. Oil level seems a little bit high though.

I filmed a video to demonstrate the problem, this is what happens with the gear level in D and the accelerator down. Car doesn't usually move but sometimes just after starting the engine it manages to get moving a bit:

 

[Wighty]

Update: The ATF seems to be good, red colour. Oil level seems a little bit high though.

I filmed a video to demonstrate the problem, this is what happens with the gear level in D and the accelerator down. Car doesn't usually move but sometimes just after starting the engine it manages to get moving a bit:

Did you measure the oil level when hot (after 20 min drive ) on level ground. , with the engine running and gearbox in Park ?
How high is high above max ?

 

[Calle1]

Did you measure the oil level when hot (after 20 min drive ) on level ground. , with the engine running and gearbox in Park ?
How high is high above max ?

Well, almost. I measured it after trying to drive for 20 minutes
the oil heated up a little but didn't get as hot as it should.

Also measured the level with the engine/geabox cold and the level was a bit over the max for 80° then already.
Wouldn't be surprised if the previous owner didn't have a dipstick and just tried to fix the problem by adding some more oil..

 

[LostKiwi]

Has the gearbox ever been split from the engine?

 

[Calle1]

Has the gearbox ever been split from the engine?

I don't know the history of the car but it's quite possible.
It's a high milage car, 805000km (about 500k miles).
So if the gearbox hasn't already been replaced once it's definitely time to do it anyway

Other than the transmission problem it seems to be in good shape and everything else seems to be working just fine.
And most surprisingly, virtually no rust! (Thanks to the dry Spanish climate I guess )

 

[alexanderfoti]

The pseudo rev limit makes me think control module or electrical, like the selector module is saying its in drive but the lever isnt.

As it's an early model it doesn't have the gear indicator. Would be good to see what the gearbox ecu shows on star for actual values.

 

[LostKiwi]

I'd be interested to measure gearbox oil pressure. Is it possible the gearbox filter isn't in properly and it's sucking air?

 

[alexanderfoti]

I'd be interested to measure gearbox oil pressure. Is it possible the gearbox filter isn't in properly and it's sucking air?

I did wonder possibly a blocked cooler

 

[LostKiwi]

I did wonder possibly a blocked cooler

Would that not give high pressure? This seems like low pressure. Of course with that mileage it could well be knackered.

 

[alexanderfoti]

Would that not give high pressure? This seems like low pressure. Of course with that mileage it could well be knackered.

I think as it's in line with the torque converter it would give no pressure as there would be no flow?

Quite possible something has broken up and blocked something.

When it goes into gear properly, how does it drive?

 

[Calle1]

I think as it's in line with the torque converter it would give no pressure as there would be no flow?

Quite possible something has broken up and blocked something.

When it goes into gear properly, how does it drive?

You could be onto something when you're talking about low pressure..
I have now had the opportunity to test it some more and the best chance to get the car moving is when it has been sitting for a while.
It does run without any wierd noises when it goes into gear however it seems to be very weak.
If you have brake it loses power and if you stop completely you're screwed - you won't get it moving again, the rev limit symptoms kicks in.

The only way to get it moving again is to restart the engine - and the longer you keep the engine turned off the better it moves.

 

[alexanderfoti]

I think the first step to do would be to drain the sump and drop the pan and take a look at the state of the filter etc.

It could be that the pump is worn out.

You could undo one of the pipes that goes to the atf cooler and start the engine. That will give you an idea of flow.

 

[Tashman]

If you cant get the gearbox warmed up enough to use the 80C marking on the dipstick, then test it cold using the 20C markings.
If its been over filled then remove some.

 

[LostKiwi]

I think the first step to do would be to drain the sump and drop the pan and take a look at the state of the filter etc.

It could be that the pump is worn out.

That was my thinking too.
When I asked if the box had been split I was wondering if perhaps it hasn't been fitted correctly and the pump drive is damaged.

 

[Calle1]

Update: Got my hands on a gearbox from for 240 GPD with 115k claimed miles on it.
Fitted it today and now it drives like a charm.

The only problem I experience now is that it goes into some kind of limp mode on the 5th gear only.
It wont rev more than 3k rpm on the 5th gear when driving on the highway

Hopefully just some old error codes that has to be deleted.. will get the car to a MB dealer on monday to hook it up to STAR.