Clonk when selecting drive

[area51]

My a-class [W168] clonks once when I select D. If I then select R soon after this it will clonk again.

The noise seems to be coming from the driver's side of the engine bay but I am not able to determine the cause.

The car otherwise drives ok, has [fingers crossed] never displayed F on the dash.

Has anyone experienced this fault or suggestions [engine mounts?]

Thanks in advance
Chris

 

[S.Speed]

Hi..
I may be barking up the wrong tree but many years ago I had an old V8 Rover 3500 Auto..
That clonked when selecting either Drive or Reverse..
In my case it turned out to be worn drve shaft joints.. This allowed a sort of backlash when engaging Drive..

Its just a thought that occured to me.

 

[television]

As above, its just a combination of wear in the splines of the drive shafts, always mad worse by those who put the box into N while at traffic lights

 

[area51]

Just spent the last couple of hours investigating this further.

When D or R is selected the clonk can acually be felt through the driver's side front engine mount and also can be heard clearly if I put my ear to the front subframe.

I have fitted a new engine mount but this has not cured the problem. [ the noise does not seem to originate from the driveshafts/transmission].

Is it possible the subframe is loose??

I would be very grateful for any help on this as this noise also occurs on pulling away from stationary and is really getting on my nerves now!

Chris.

 

[television]

I do not know enough about the A class to comment

 

[area51]

Spent some more time trying to track down this clonk.

Probably not the kind of approach to diagnosis that Mercedes would recommend but..

I removed the [brand new] front engine mount and drove around for a while without it [ there are still 3 mounts left to prop the engine up!].

The car was quiet [no clonk] although obviously the engine could be felt moving around a bit more than usual.

Question is, what does this actually tell me? Should I replace the other mounts, or does the fault lie with the front mount that I removed temporarily?

Chris

 

[television]

Can you see if the other mounts have collapsed . SAM is the best one on these faults

 

[area51]

Can you see if the other mounts have collapsed . SAM is the best one on these faults

Thanks for your reply.

All the other mounts look ok although this does not mean that they are of course.

Chris

 

[area51]

Has anyone had experience of the front subframe clicking on pullaway?

Any ideas on how to cure it?

Chris