W211 7g transmission oil change question

[boxer 01]

After getting my suspension sorted. I have decided to have a go at repairing a leaking transmission sump gasket, and from what I've learned I think a full transmission service should be done at the same time. What I can't really work out is when I drop the old oil does the car need to be up to full operating temperature, or does it not matter, some people have mentioned the oil cooler thermostat needing to be open. I don't intend on messing with the cooler but I will do the torque converter.

 

[geoffus]

When I did my 7g + i did it cold, it took 9 litres to fill so I imagine I got all of it out. I didnt realise there was a transmission thermostat.
Its more important to refill the transmission with the correct level at 45 degrees.

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[DSM10000]

Does it have a thermostat for the transmission?

I have never heard one being mentioned in threads here.

 

[DSM10000]

After getting my suspension sorted. I have decided to have a go at repairing a leaking transmission sump gasket, and from what I've learned I think a full transmission service should be done at the same time. What I can't really work out is when I drop the old oil does the car need to be up to full operating temperature, or does it not matter, some people have mentioned the oil cooler thermostat needing to be open. I don't intend on messing with the cooler but I will do the torque converter.

You really should disconnect the lines to the oil cooler to drain as much fluid as possible.

This is one of those jobs I would leave to a specialist. I know some members have changed the fluid at home and on their drives but for the small cost saving of around £60-£70 by the time you buy the fluid, filter and delivery tube plus checking the level after refilling at 45 Deg C.

It is a potentially expensive and complex component to fix if you get it wrong.

 

[W1ghty]

Hard to beat this cost for fluid £61/8L

Pardon our interruption...

www.ebay.co.uk

I think my ZF filter/gasket and bolt kit was £22 from AUTODOC in a sale .

 

[W1ghty]

You can drain it cold without issue , but the TC drain plug is tiny . Depending on how long that would take to drain cold I would think it would speed up massively if it was hotter ?? Maybe run the car for 15/20 mins .
This was my first attempt at doing the job

Mercedes E320cdi 722.9 DIY Gearbox oil change

Just finished the gearbox oil change . I'm embarrassed to say it probably took about 5 hours over yesterday afternoon and this morning . God know where the time went , probably lots of tool retrieval from the garage and a healthy dose of second guessing . I didn't intend to start yesterday ...

forums.mercedesclub.org.uk

 

[boxer 01]

You can drain it cold without issue , but the TC drain plug is tiny . Depending on how long that would take to drain cold I would think it would speed up massively if it was hotter ?? Maybe run the car for 15/20 mins .
This was my first attempt at doing the job

Mercedes E320cdi 722.9 DIY Gearbox oil change

Just finished the gearbox oil change . I'm embarrassed to say it probably took about 5 hours over yesterday afternoon and this morning . God know where the time went , probably lots of tool retrieval from the garage and a healthy dose of second guessing . I didn't intend to start yesterday ...

forums.mercedesclub.org.uk

This makes sense and the warm oil will probably drain quicker and maybe less chance of leaving any dregs. I've ordered 8lt. Fuchs titan 4134 and I already have 1lt. I will be getting the other bits for service from MB.

 

[DSM10000]

How are you planning to drain the T/C?

 

[boxer 01]

How are you planning to drain the T/C?

When I start I will be leaving the car in neutral then when I'm underneath after removing rubber grommet the TC drain plug should be seen if not turn engine till plug is showing then remove plug and drain, I am planning on getting a new replacement.

 

[DSM10000]

Are you sure there is a drain plug?

Mercedes deleted this from a lot of the transmissions.

This is why MB specialists drain from the oil cooler pipework.

 

[markjay]

Are you sure there is a drain plug?

Mercedes deleted this from a lot of the transmissions.

This is why MB specialists drain from the oil cooler pipework.

I was told by the dealer (MB Brooklands) that the 7G+ does have a torque converter drain plug, when they replaced the ATF on my car.

However, it is not clear if the OP has the 7G or 7G+ transmission.

I also understand that in spite of the transmission having a torque converter drain plug, the process of draining it is both slow and cumbersome.

And, I don't know if the ATF cooler is physically higher or lower than the torque converter drain plug line, so no idea if it gets drained as well. I've never heard of a thermostat though.

 

[boxer 01]

Thanks for your replies. I am going into the dealers soon and will ask about the TC but when my gearbox was serviced last I was told the torque converter was drained. to be honest my main concern is to stop the transmission sump leak, if I can drain the TC it will happen if not I will have some oil spare.

 

[W1ghty]

Are you sure there is a drain plug?

Mercedes deleted this from a lot of the transmissions.

This is why MB specialists drain from the oil cooler pipework.

He probably does have a drain plug for the TC because his car is a year older than my E320cdi (I have one) . If he doesn’t that’s £4 max he’s wasted for the plug . There is a rubber bung that can be removed when he is under the car , so when the engine is rotated he will see it in gearbox housing .
If it’s not there he can either disconnect an oil cooler line or do a sump fill and flush instead .
He has a 7g box (no + )

 

[DSM10000]

He probably does have a drain plug for the TC because his car is a year older than my E320cdi (I have one) . If he doesn’t that’s £4 max he’s wasted for the plug . There is a rubber bung that can be removed when he is under the car , so when the engine is rotated he will see it in gearbox housing .
If it’s not there he can either disconnect an oil cooler line or do a sump fill and flush instead .
He has a 7g box (no + )

Yes , aware it's a 7g.

Mine doesn't have a drain plug either

 

[W1ghty]

Yes , aware it's a 7g.

Mine doesn't have a drain plug either

Apologies , the 7g bit was for @markjay

 

[DSM10000]

Apologies , the 7g bit was for @markjay

Not an issue

 

[W1ghty]

Not an issue

If it was , I would suggest meeting in our Y fronts at dawn covered in olive oil for a fight to the death wrestle

 

[DSM10000]

If it was , I would suggest meeting in our Y fronts at dawn covered in olive oil for a fight to the death wrestle

I nearly dropped my wine

No Y fronts though!

Boxers

And Rapeseed oil

 

[Petrol Pete]

The dreaded lack of T/C drain plug raises it's stupid ugly head again. I must stop banging on about it .....but WTF were they thinking ?

Yes , I know ...'sealed for life'.....

 

[boxer 01]

The dreaded lack of T/C drain plug raises it's stupid ugly head again. I must stop banging on about it .....but WTF were they thinking ?

Yes , I know ...'sealed for life'.....

And the refill procedure leaves a lot to be desired surely a dipstick is the most sensible solution, even for regularly checking during the cars lifetime. Maybe too much thinking went on.