[burkey]

Hello

I have done quite significant searching on this and similar search phrases and have not really found the information I'm after.


The car is making a really loud knock/clunk/bang from what feels like the left hand rear that I can feel through the car when I take off.

This only happened this afternoon close to home and I have crawled home at 30km/h. I am baffled at what's happened.

The car is a 2009 335i Sport. 6spd manual. 2 months old and has only done 2500km.

Whats it feel like?
It sort of feels like the left rear brake is taking a huge grab at the rotor for a split second and then releasing. I can feel this through the seat of my pants as a jolt and it sounds like drive motion is either being stopped (by the brake grab idea) or something else in the drivetrain is making this noise after taking up slack / load.

Some symptoms

1. Regardless of how gently I take off, regardless of how slowly i build speed, it will go 'bang' once in first and also again 'bang' once I have changed into second
2. Going around corners also produces the same single 'bang'. Mind you this is when I am absolutely crawling home being as gentle as humanly possible to the car..

Has anyone experienced something like this ?

thanks
burkey

[E90330iS]

animal stuck?

[burkey]

I should also mention I have jacked up the car and had a look and a poke around.
Everything feels solid and all bolted together....

Regardless of this, it is being towed to dealer today.

[samurai1200]

considering your first symptom, it sounds like a tranny problem. no clue where to start pointing fingers tho. no BANG with gears 3-6?

[HermesRider]

I broke an axle in my '87 e30 and it sounded exactly like that. BUT, it only happened once and I had zero power afterward... My guess is a drivetrain issue though. Let us know what they find!

[nicknaz]

might be the differential is broken and locking up. i would have guessed axle, but whenever i've broken an axle its just one loud bang and then (obviously) no more movement. it does sound like a drivetrain issue so definitely get it towed and looked at. don't drive it

if it was a sticking caliper it would not be making the banging noise

[undecided]

I heard jackhammer like noises but once the car was turned off they went away. Did you hear anything "hydraulic" sounding? I did not feel any difference in the way the car drive while the noises were present.

[Xiaofeng]

Welcome to E90post, burkey, although I wish it was under better circumstances though.

It sounds to me like you have a broken rear differential. The cornering and acceleration jolts and the "banging" noise would point to that, and since it's reoccurring, it shouldn't be an axle. Definitely have it checked out. Call BMW Assist and have it towed to your dealership, or you may end up doing more damage to it.

[burkey]

Hello,

I have an update & solution.

The constant velocity joint was damaged. The bearing races within the joint itself have broken into several pieces, with ball bearings and miscelaneous broken bits.

My dealer was more than suprised it was broken.
This has been fixed under warranty and there have been 5 others apparantly in Australia that have had this similar fate, so maybe there was a faulty batch of half shafts out there somewhere...
I asked if I could take the half shaft to hang on the wall as a momento... Negative ghost rider; part off to fatherland for examination.

Regardless, car is fixed and I have to say my dealership (Mornington BMW) have done an excellent job helping me out. Two new loan cars, excellent tow, helpful etc etc. Cant praise them enough.


Given the car is 100% stock, I am amazed that none of you 400hp/400'lb tune guys have broken half shafts....

[samurai1200]

interesting... maybe it's an aussie delivery thing?
or potentially just non-US cars (given that we are the only ones to drive lefty).