[flightrisk]

My W123 has a manual 5 speed. When pulling away in 1st, if I don't release the clutch gently I get a slight clunk.
This also happens when changing to 2nd and to a lesser extent 3rd.
There's obviously some play somewhere but I'd like advice where to look first.
If I grab the prop shaft, should there be any rotational play at the diff end? What about the gearbox end?
I read somewhere it could be engine mounts, but these have been changed recently along with gearbox mount and diff mount.
Could this be a sign the clutch needs changing?

 

[tsharkey]

What about the centre bearing on the drive shaft and / or the flex plates ...... I had a worn centre bearing that used to shudder when taking off (auto trans in this case).

 

[flightrisk]

Hi,
The centre bearing and support were changed last year too.

 

[plinker17722]

If not a good brand they have now gone bad .Mercedes parts only for these rubber flexi plates .Check it again to be sure .Along with propshaft nuts and bolts .I have had the nuts come loose on one car i had ,And if those are ok then it would be final drive play .;

 

[flightrisk]

Hi, thanks.
Just to be clear, the centre bearing and support have been changed, but neither of the flex discs.
They both appear OK but I realise it's better to examine when off the car.
Could worn flex discs cause the symptoms I'm getting. I assumed they would have to look pretty knackered on the car if they got to the point of making a clunk.
Just about only happens in 1st and 2nd.

 

[Nutz 4 Benz]

What about those plastic dog bone looking things on rear axle hubs. Forgot the name of them..sway bar link?

 

[flightrisk]

Replaced those last year too.

Forgot to mention I can reduce or even stop the clunk if I release the clutch very slowly.

 

[tsharkey]

I gather it happens when the torque is rapidly applied from releasing the clutch (not too slowly). ​

Assuming the cross member if bolted on tight, as is the trans to the car​

, looks like it is gear box / clutch related as we have eliminated everything else.....

 

[flightrisk]

That's what I'm thinking too.
I do sometimes get some clutch judder when cold, but that seems to be less frequent now that I use the car every day

 

[tsharkey]

and the front end is all good (ball joints etc ?)

 

[Nutz 4 Benz]

and the front end is all good (ball joints etc ?)

I was thinking where the sway bar connects to firewall. Had similar clunk issue on my once upon a time W116 many years ago.

 

[flightrisk]

sway bar bushes replaced a few months ago and the problem has been present before and after.
Upper control arms, rear subframe mounts, shocks and all steering arms changed recently.
Car only has 107000miles so I was hoping gear box and diff will be OK.
No apparent play in lower ball joints.

 

[tsharkey]

I have had a cracked rear trail link (on an imported UK wagon) that was caused by internal rust. The trail links arms OK

 

[flightrisk]

I managed to have a good look under the car today.

Does this flex disc look OK?

If I hold the flex disc and turn the prop shaft, I can close the gap marked a little.
Should I be able to compress the flex disc like that by hand.

Theres a small amount of radial play when I turn the prop shaft and I can hear a clunk.
Difficult to tell if it's from the flex disc or inside the gearbox.
The car was in first gear when I did the above.

There's very slight rotational play in the u joint as well, perhaps 3mm.
Is that normal?

 

[tsharkey]

Nope that is not OK - Did you say they were new ?

 

[flightrisk]

Flex discs aren't new.

 

[flightrisk]

I started replacing the rear flex disc today.
It was pretty easy to remove all the bolts but a nightmare to push the drive shaft forwards to give space to get the old disc out.

I managed it eventually, but there's no way I'll get the new disc in. Centring bush is stuck in drive shaft so it's going to be regreased and stay.

I now realise that I should have loosened the 2 bolts that secure the centre bearing mount.

Does doing that allow the driveshaft to be moved forward better? It just keeps springing back and not giving enough space at present.

I could see the rear portion of the drive shaft sliding forward and I haven't loosened the 46mm clamping nut. I'm thinking it shouldn't be able to move like that?

 

[flightrisk]

I managed to replace the rear flex disc but still have the clunk.
I mentioned the play in other posts but here's a vid of the noise from the diff end when I rotate the prop shaft. Wheels on the ground and car in neutral.
Is this amount of play normal and if not, what could be the cause?

http://instagr.am/p/CDyylKOj3F5/

 

[plinker17722]

Driveshafts will need replacing .. Get a garage to look at it first .

 

[Nutz 4 Benz]

Parking pawl in transmission maybe worn.