Jerky gearbox

[Wighty]

Mercedes Benz of Southport, 300 miles south of me but 2 miles from me mums. The nearest dealer to me is over 100miles away

I've got relatives in southport , I'll make a mental note , thanks for the tip

 

[Terry Wilkins]

If it were me I would travel to a decent Merc Indy who has done this a number of times , I believe that the gearbox needs connecting to a Merc Star computer to get a correct level at the correct temperature . If there is no evidence of the oil and filter being changed before in the cars service history you need to drop what you are doing and get it done asap . It should cost around £250 at an Indy .
Where do you live so someone can recommend an Indy ?

Between Camborne and Redruth in Cornwall. I'm an Essex boy originally. I hope someone can recommend an indy as Imuch too far away from the Merc dealer.

 

[Wighty]

The only one I know heavily recommended is Steve at Avantagrde Mercedes Clevedon ,near Bristol . He is regularly on this site...going to be well worth a day out

 

[star]

+1 for Steve, make who ever you use can check for software updates.

 

[Arudge]

If it were me I would travel to a decent Merc Indy who has done this a number of times , I believe that the gearbox needs connecting to a Merc Star computer to get a correct level at the correct temperature . If there is no evidence of the oil and filter being changed before in the cars service history you need to drop what you are doing and get it done asap . It should cost around £250 at an Indy .
Where do you live so someone can recommend an Indy ?

The 7g doesn't need STAR to achieve the correct level, it has a fill/drain hole and you simply pump ATF in until it starts running out again, exactly the same as filling a differential. Its a better idea than a dipstick as you can't overfill and you can't really get it wrong.

In saying that.......

 

[Wighty]

The 7g doesn't need STAR to achieve the correct level, it has a fill/drain hole and you simply pump ATF in until it starts running out again, exactly the same as filling a differential. Its a better idea than a dipstick as you can't overfill and you can't really get it wrong.

In saying that.......

I know what you mean , I mentioned the Star part because isn't that how the Merc people get the temp correct in order to get the level right at 80 something degrees ? ?

 

[Arudge]

I know what you mean , I mentioned the Star part because isn't that how the Merc people get the temp correct in order to get the level right at 80 something degrees ? ?

Yes it is, but there are other methods like an optical thermometer or just a half hour drive will push the temp up to where it should be.

But try and understand what this is all about....

If the ATF level is too low the pump will draw air, which will foam the oil and the oil will loose all of its hydraulic qualities, it's full of air.

If the level is too high then the oil will be within reach of rotating parts which will also foam the oil as those rotating parts throw the oil everywhere.

You will have exactly the same problem whether the oil is too low or too high, air in the oil leading to loss of hydraulic pressure=strange goings on.

In reality, as long as the oil covers the intake when its cold and doesn't expand up into the rotating parts when its hot then your good to go.

 

[steveq]

I suspect that the main dealer is just going to drain the sump and change the filter for that price - they won't drain the torque converter.
That is the 'standard' change and takes about 5 litres of ATF.
Draining the TC adds about 3 litres more and takes more time.

You don't need STAR to do the ATF change but you do need to monitor the transmission fluid temp for the level measurement. An icarsoft i980 OBD reader will show the transmission fluid temp -- I'm sure other OBD readers will show it too.
I read elsewhere that external temp reader are inaccurate.