Hi Guys. I have a noise that sounds like a loud "crack" that comes from the rear suspension (poss nsr) when I change from going forwards to backwards and visa versa. If I get in in the morning and reverse off the drive it moves anything from 3 to 10ft then this crack noise. Just once and it might do the same later on. Again from a standstill. Its definitely not Haldex or Diff as these were checked and serviced at Bell recently. Because its so sporadic I cant replicate it when jacked up.
I was wondering if anyone else had experienced this and could give me some pointers? In the back of my mind I am thinking it might possibly be a bush in the nsr suspension that moves enough when the torque of either drive applied or braking? Anyone had the long trailing arms from under floor to lower rear knuckle go?

Thanks in advance for suggestions.

check the handbrake drum shoes, they may have come away from back plate. This would cause a 'correction' noise on both back and forward motion.

Thanks for the pointer but already checked those. Its definitely susension or drive related and a really loud crack. If it went crack crack crack etc I would say it sounds like a driveshaft maybe.

Going along the suspension line ...... is it a broken coil spring ??? Check where the spring meets its mount at the bottom of the lower arm. Measure the coil spring on both sides, whilst vehicle is on level ground.


Try this link .....
https://www.freel2.com/forum/topic34921-5....oil+spring

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Are you reversing on lock, and if so could it be transmission wind up. It shouldn't happen on a FL2, but I know it happens on some other 4x4 SUVs. I have witnessed it in my brother's Mercedes.

https://www.freel2.com/forum/topic33275.html?highlight=mercedes FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 76k+ miles) (MY2015)

Largered wrote:

Going along the suspension line ...... is it a broken coil spring ??? Check where the spring meets its mount at the bottom of the lower arm. Measure the coil spring on both sides, whilst vehicle is on level ground.


Try this link .....
https://www.freel2.com/forum/topic34921-5....oil+spring

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IanMetro wrote:

Are you reversing on lock, and if so could it be transmission wind up. It shouldn't happen on a FL2, but I know it happens on some other 4x4 SUVs. I have witnessed it in my brother's Mercedes.

https://www.freel2.com/forum/topic33275.html?highlight=mercedes

Disable the haldex - there is a fuse you can remove or just unplug it from underneath - it wont do any damage. But it will disconnect the prop shaft from the rear diff and may help to find the area at fault.

Also get someone alongside to listen for the "crack" to help identify its source Jules