Good evening, wondering if anyone has experienced something similar and knows what would be the fix.

Whenever I go around 90-110 km/h (60-70 mph) and release the accelerator pedal, I hear a knock from front end of car. This also happens if I floor the accelerator pedal from low revs. I can hear the knock even when I switch off the cruise control on a highway.

Another way I can replicate the knock is if I rapidly release or push the clutch pedal when in starting in 1st gear. Also, when switching from any other two gears, If I don't match the revs, and rapidly release clutch, the knock will be there. It doesn't affect driving in any way but it is very annoying. Might be unrelated, but I think I also do feel an excess vibration through the floor and seat.

As I have replaced pretty much the whole suspension (Bilstein shocks+kyb springs+skf front mounts, lemforder control arms, lemforder droplinks, refurbished steering rack + all new lemforder tie rods, delphi antiroll bar bushings), im pretty much out of options.

Currently I suspect it could be the transmission mount (although seems to be good after visual inspection), propshaft or dual mass flywheel. Could CV joints also cause this? Can anyone share their experience?

Sounds very similar to this :

Thank you!

Have you checked the lower engine torque bush assembly?
These are known to fall apart in time, as they are subject to an amount of oil contamination from drips from the breather circuit. 2009 Rimini Red SE TD4. Soon to be sold.
Hyundai Ionic 5 Ultimate on order.
Gone. 2006 Tonga Green i6 HSE.

Thanks for your reply, Nodge.

Do you mean this bushing?

Yes. I had to replace mine, as it had fallen apart. It's easily checked though. 2009 Rimini Red SE TD4. Soon to be sold.
Hyundai Ionic 5 Ultimate on order.
Gone. 2006 Tonga Green i6 HSE.

This is the one I used

https://www.ebay.co.uk/itm/334631346049?ha...R4bmlvq2YQ

Jesus, ebay is expensive. Got quoted 19 EURO for the same Febi bushing from local supplier.

But thanks for advice, when I get back to farm, I will inspect with a hope of bushing being bad. Will keep this post updated.

So, a small update. Im in a process of changing both transmission mount and lower engine mount. Just changed the one on transmission, but the old one was in good condition. The only issue i found was that the 4 bolt holes where mount is supposed to be bolted to the body of car, were not centered. Bolts touched the body of mount. Is it supposed to be like this?






I will soon go and also change the engine mount, but I really don't think that these mounts will solve the problem, since both of them are reasonably good. Any other ideas? CV axle on left side? Flywheel? This is very weird, because this knock is driving me crazy, but I do not have any other symptoms of a bad flywheel.

One other symptom that I didn't mention - When braking at red light, regardless of wether the clutch is pressed or not and regardless of whether the car is in gear or not, when speed drops at around 20kmh, I can feel and hear one small knock in gear lever.

Update. After changing all engine mounts, there was no difference. Decided to change transmission oil, and it improved the knocking slightly. After doing around 2000km after oil change, the situation has improved a lot, about 30% of knocking remains. If it doesn't disappear 100%, i will try to use some gearbox oil additives.

That's interesting, I just posted this a few minutes ago:

https://www.freel2.com/forum/topic38967.html

my knock sounds similar to the one in the video you linked but a little quieter.

Does my desctiption sound similar to your experiences?

Indeed it seems that we have the same problem, ransoman, it would be of a high value if we share information as we move forward.

So the single click when braking or deceleration is most probably causes by reverse lock solenoid, located under the leather trim on gear lever. As i have found out, usually it is cured by disconnecting all plugs and connecting them back, if not - changing the solenoid.
But, as for the click when switching gears or pressing clutch, my strong feeling is that it is in gearbox. Oil change helped a bit. I will add an additive and see if anything changes as there is nothing much to lose. Worst case - replace gearbox.

Hi,

What are the mileage of your car?

I have had a similar knock for the last year, but have not started to investigate it yet. Just implemented a smoother driving style

99'000 miles.

I am currently going with the theory that it is the Haldex clutch, but I am not 100% sure on that. It very specifically sounds like it is coming from the front right road wheel but I have had it in there air 4 times now looking for faults and I can't find anything wrong at all.

OK. Mine @ approx 200.000miles / 320.000km`s. Found my lower engine mount shot, so will replace this one and hope that is the issue on mine.

You can try to remove the fuse (FB6?)for the Haldex and see if your issue disappears?

Ok, so there is three of us now, we HAVE to figure this out.

In my case, im quite sure it is not haldex, since the pump has gone and haldex is non operational. Currently I suspect cv axles (although they seem fine) or, in the worst case, fault in a gearbox, although there are no other symptoms apart from knocking occasionally when pressing clutch or starting driving from a full stop. Switching gears is smooth, no grinding noise, nothing. I suspect this, because the situation improved after gearbox oil change.

Just to find common things - do you both have manuals,right?

And btw : I don't know if you also have this symptom, but whenever the speed goes under 20 kmph, there is a slight knock in gear lever. Im 99% sure its reverse lock solenoid, and usually it is cured by disconnecting and connecting back the connectors under gear lever trim. Will try to do this as soon as I can.

Mine is a manual. Replaced clutch for about 3 years ago together with the DMF (used, low mileage item). My "knock" is definitely not from the reverse lock solenoid in the gearshift lever. That one is hardly noticeable. I replaced this one for a year back as it failed nearly completely.

Still waiting for my lower engine mount. I put a few pennies on that one, it is clearly shot...