7G Gearbox 'jerk'...HELP PLEASE......

[SimonE56]

I have just bought a 2008 Clk with 18,0000 miles.
It is fitted with the 7G gearbox.
The car drives amazingly well.....and has a full MBSH.
The only issue is that sometimes there is a 'jerk' when selecting 'D' or 'R' gears.
This only happens randomly.
(It happens going from 'N' to 'D' or 'N' to 'R' but only occasionally...there are no bangs or other noises and it just fells like an older car with slightly high revs that is just a bit too keen to get going...ps the revs on my car are steady at about 600rpm !!!!!)
It doesn't seem to matter if the car is hot or cold.
The car then continues to drive beautifully and changes perfectly up and down (And kick down !!)through the gears seamlessly.
There are no faults stored on the diagnostic.
The oil level is fine.
The oil is clear, of the correct grade, and doesn't smell of burning or anything else.
I reset the torque converter but this doesn't seem to help.
I am tearing out what little hair I have left and don't really know what to look at next...
I would be really grateful for some guidance.

[t400ble]

Merc dealer taken a look?

[gvij]

Its a used car so its used after all. Cars start deteriorating from the moment they leave the factory. If the jerk is only from N through the gate it wont affect the drive. I suppose a Merc dealer will want to change the gearbox or something else major ,ecu? so its not really viable to go that route on a 08 machine.

[kev b]

I had a similar, not identical, problem with a BMW, the dealer installed an updated gearbox map which cured the fault.

I don't know about the cost as it was under warranty, it won't cost anything to speak to the dealer though in case there is a known fix.

[SimonE56]

Thanks guys I wondered if an engine / gearbox software update might do the trick?

[Mikey_W]

Get MB to update the engine and gearbox software. If that doesn't work, then get them to carry out a gearbox adaptation..

[SimonE56]

Thanks...I hope this works
I was hoping someone on here may have had a similar experience????

[BE57 TOY]

I have the same clunk on my A3 auto and am led to believe its normal and not to worry about it!

[SimonE56]

Fingers crossed...any other thoughts ?

[anonymous-user]

Silly question, but is the idle right. If just a few hundred above normal and you will get clunks on engaging D and R from stationary.

[SimonE56]

The idle is perfect and steady at about 600 rpm....thanks !!!!