hi guys i hope someone can help me, i can hear a knocking sound from the rear of my e55 when i set off.
if i put it in manual mode in 1st gear and just put the throttle down i can hear it all the time.
it only started a week ago this noise.
i have emptied all the car out,ive had it on the lift checked suspension,exhaust etc and still cant find the cause.
if anyone has any ideas please help as this is very annoying.
thank you

 

I could be a number of things....

1. Rear Airmatic strut.
2. Bushing.
3. Subframe movement.
4. Exhaust system hitting something.

Sounds like you already checked underneath but if it were me, I would get someone in the back seat so I could at least try and isolate it to the left, right, or center. I would then get the car back in the air and check the subframe bolts with a wrench, use a pry bar to try and deflect a suspension bushing, yank the exhaust around to so if it is clunking (put some gloves, grad the mufflers cans, and start shaking), and check the Airmatic strut for signs of leakage or damage.

Hope this helps as there are lots of things that can cause a clunk!

 

come to think of it, it could be the rear strut as 2 times in the last two weeks whilst driving the symbol with the car and an arrow pointing upwards has appeared on the malfunction screen. but it goes off after a while?
ive checked all the bushings with a pry bar and have checked the exhaust,
what do i look at to see if the struts making the noise? if it was leaking would it still make a noise?
i will also check the subframe for movement,what is the best way to check this?

thank you

 

I had a clunk at take off and it was the subfame mounts. Had them replaced (Covered 100% by my Chrysler warranty). All better now!