E320 CDi Transmission Clunk

[Razoo]

2004 W211 E320 CDi (3.2 Ltr. Straight-six)

Over the past few weeks I've noticed that as I gently brake to pull up at a road junction or similar, there is sometimes a tangible and audible 'clunk' just as the vehicle comes to a stop and the transmission disengages whatever gear it was in. It doesn't happen every time, but it's often enough to concern me.

The transmission had an oil & filter change in July 2008.

Any ideas anyone?

Thanks

Razoo

 

[television]

Is the fluid low and moving to the front of the box when braking, do check the level

 

[Razoo]

Is the fluid low and moving to the front of the box when braking, do check the level

Checking the transmission oil level is right at the top of my list of things to do. I would have done it days ago, if I had a transmission service dipstick (I do have one on order).

I drove the car to my local MB Main Dealer on Saturday morning to ask if they would check the transmission oil level for me, but they wouldn't because they were too busy for the number of staff they had in!

Mike

 

[Parrot of Doom]

There was a member on here a while back who had a similar problem, IIRC it turned out to be the rear subframe bushings.

 

[BlackC55]

Second that one POD.

Really common problem now on the 210.

 

[television]

So just making this clear, is it that the box is moving it out of D when braking

 

[BlackC55]

Nope, its the rear subframe banging away.

 

[television]

Ok it was the dropping out of gear bit that puzzled me

 

[roofless]

2004 W211 E320 CDi (3.2 Ltr. Straight-six)

Over the past few weeks I've noticed that as I gently brake to pull up at a road junction or similar, there is sometimes a tangible and audible 'clunk' just as the vehicle comes to a stop and the transmission disengages whatever gear it was in. It doesn't happen every time, but it's often enough to concern me.

The transmission had an oil & filter change in July 2008.

Any ideas anyone?

Thanks

Razoo

sounds odd the gear disengages. my first thought was a abs sensor on the way out as you would get a kick just as it stops but not every time so will be keen to see what it is in the end

 

[Razoo]

sounds odd the gear disengages. my first thought was a abs sensor on the way out as you would get a kick just as it stops but not every time so will be keen to see what it is in the end

The 'clunk' displays all the characteristics of the transmission dropping slightly roughly out of gear on overrun. At the time my foot is still on the brake as I'm bringing the car gently to a halt.

You would get a similar effect with a manual car if you were slowing on overrun to a stop and pulled it out of a low gear at a few mph without depressing the clutch.

It's possible an ABS fault could produce a similar effect.

First check will be the transmission oil level as Television suggested. I don't think it's the rear subframe bushes, but you never know.

I report back as soon as the problem is identified. I can't produce the 'clunk' on demand, so it's going to be one of those elusive faults to track down.

Razoo

 

[ShinyF1]

I have the 'thunk', but no issues with dropping out of gear. Olly drove mine recently when I left it with him for some work and he is sure my problem is subframe bushes.

Must try to get to see him after christmas...

 

[television]

I have the 'thunk', but no issues with dropping out of gear. Olly drove mine recently when I left it with him for some work and he is sure my problem is subframe bushes.

Must try to get to see him after christmas...

I would let Ollie get fit again after his holiday first

 

[television]

The 'clunk' displays all the characteristics of the transmission dropping slightly roughly out of gear on overrun. At the time my foot is still on the brake as I'm bringing the car gently to a halt.

You would get a similar effect with a manual car if you were slowing on overrun to a stop and pulled it out of a low gear at a few mph without depressing the clutch.

It's possible an ABS fault could produce a similar effect.

First check will be the transmission oil level as Television suggested. I don't think it's the rear subframe bushes, but you never know.

I report back as soon as the problem is identified. I can't produce the 'clunk' on demand, so it's going to be one of those elusive faults to track down.

Razoo

The engine and box does not have to move by much to move the shift to N,,all it needs is the selector rod a little biased to the N and engine mount bad, to let it pull the shift rod a touch

 

[Razoo]

The engine and box does not have to move by much to move the shift to N,,all it needs is the selector rod a little biased to the N and engine mount bad, to let it pull the shift rod a touch

The clunk hasn't occured lately and I have checked the transmission oil level, which is halfway between the upper and lower 80 degree C level marks on the service dipstick.

I was going to top the oil up, but now I have another discrepancy. The transmission oil & filter were changed in July 2008 by a MB Main Dealer. I bought some transmission oil with exactly the same MB part code as the oil used for the oil change (I took the part code off the MB invoice). However, the oil in the transmission is straw coloured, whilst the top-up oil I have just bought is red.

Nothing is straightforward, is it?

Any thoughts anyone? Are the straw and red transmission oils likely to be compatible, or shouldn't I mix them?

Thanks,

Razoo

 

[Parrot of Doom]

It could be the newer stuff, which I believe is backwards-compatible. As long as its MB branded and specced for your gearbox it should be ok, but you may want to get a second opinion on that.

I wouldn't top it up if it's in the middle on the dipstick.

 

[television]

The clunk hasn't occured lately and I have checked the transmission oil level, which is halfway between the upper and lower 80 degree C level marks on the service dipstick.

I was going to top the oil up, but now I have another discrepancy. The transmission oil & filter were changed in July 2008 by a MB Main Dealer. I bought some transmission oil with exactly the same MB part code as the oil used for the oil change (I took the part code off the MB invoice). However, the oil in the transmission is straw coloured, whilst the top-up oil I have just bought is red.

Nothing is straightforward, is it?

Any thoughts anyone? Are the straw and red transmission oils likely to be compatible, or shouldn't I mix them?

Thanks,

Razoo

It goes that colour as soon as you put it in the box, so thats normal

 

[Razoo]

It could be the newer stuff, which I believe is backwards-compatible. As long as its MB branded and specced for your gearbox it should be ok, but you may want to get a second opinion on that.

I've just spoken to the MB Main Dealer who carried out the transmission oil change on my E320 CDi.

The oil used was Part Code: MA001 989 45 03/10 (ATF 3353 - colour red). This is not the latest oil.

The latest oil (allegedly) is Part Code: MA001 989 68 03/10.

I am advised that these two oils should NOT be mixed.

According to the MB Main Dealer, the way to change to the new oil is to:

1. Disconnect the oil cooler return pipe at the gearbox (banjo connector).

2. Let the engine run at tickover and pump all of the old oil out (turn the engine off when the oil flow starts to splutter).

3. Put 1 litre (or 2 litres, if you're feeling affluent) of the new oil into the transmission.

4. Start the engine and let it run at tickover and pump the oil out, thereby purging the system of (most of) the old oil (turn the engine off when the oil flow starts to splutter).

5. Reconnect the oil cooler return pipe (fit two new sealing washers to the banjo connector).

6. Fill up with new transmission oil.

7. Run engine and check oil level at 80 degrees C. Top-up as necessary.

Presumably this procedure will empty the torque convertor. MB assure me that running at tickover to pump the transmission oil out will not cause any damage. I guess a new transmission oil filter should also be fitted.

I wouldn't top it up if it's in the middle on the dipstick.

Having bought 2 litres of top-up oil, I was keen to justify the expense by squirting a drop into the cogbox

Razoo

 

[Razoo]

Chameleonic Transmission Oil

It goes that colour as soon as you put it in the box, so thats normal

Yes, that's exactly what the MB Main dealer has just confirmed.

Thanks,

Razoo

 

[television]

Yes, that's exactly what the MB Main dealer has just confirmed.

Thanks,

Razoo

I must say that your post above is very good way to do it, and should help others doing the job

 

[wingco]

Don't bother with the main dealer

Razoo

If you are in Newbury in Berkshire, don't bother with the main dealer. Call Darren at Protech on 01635 299811. He is in Kingsclere. He only works on MB's, and used to be at the main dealer in Newbury. What he does not know about Merc's is not worth knowing.

He always services and repairs my car, and has never failed to diagnose a problem and fix it quickly and at a reasonable price. You will see many cars in his workshop that used to be looked after at the main stealer in Newbury................