C34 rear end clicking at slow speed

[ls_stag]

C34 rear end clicking at slow speed

Hey guys, having some noise from the rear end of my '99 RS4S with LSD (I think its a 2-way), seems to be happening more but the weather here has got really cold lately (a high of around zero C and a low of minus 5 C) so that might be related.

At slow speed, I'm hearing a clicking/snapping/metallic click noise coming from the rear. Sounds to me like it's rear left, but my wife thinks its rear center/left/right. It is not rhythmic as far as I can tell. ie if I'm going along it doesn't happen at a regular interval. Has been happening a bit lately around 40kph and even 60 kph once or twice. I don't notice any movement or jerks/etc, just the noise. Really want to address it if its something wearing out, etc.

Doesn't seem to be tied to bumps in the road surface, so I don't think its the coilovers but who knows. Sounds really similar to a frontend noise that turned out to be the sway bar link, but it's not as predictable with the rocking of the car like that problem was.

In case its related, theres some vibration in the drivetrain from time to time which could be front end but could be rear end related too.

Cheers!

[Trex]

clicking in rear site:www.sau.com.au

Copy and paste that into google.

 

Honestly it could be anything, arms, driveshafts, diff, etc. You'll most likely have to get out some tools and have a poke around, get a big pry bar and put some pressure on all the pivot points on the arms and see if anything moves.

[ls_stag]

Thanks @Trex - hadn't found a lot through the site search.

 

[KiwiRS4T]

Low pad warning?

Parking brake not fully released?

[Trex]

Low pad warning?
Parking brake not fully released?

Low pads would be a scraping sound

[V28VX37]

I had a low speed scuff and a click after installing my new Nismo 1.5-way, turned out to be two unrelated issues:

• Handbrake setup binding
• Tail shaft counterweight just touching the mid muffler at certain revs, making a clicking noise

Neither issue was diff related but I was super attuned to all noises from the rear after getting the LSD done

[ls_stag]

Thanks guys. Gonna get under it this weekend and do a visual plus moving things to see if I can reproduce. Definitely happening quite a bit today. Doesn't seems to affect driving.

[V28VX37]

Thanks guys. Gonna get under it this weekend and do a visual plus moving things to see if I can reproduce. Definitely happening quite a bit today. Doesn't seems to affect driving.

Good plan. Put the rear on stands and run it in 1st gear & listen carefully next to each wheel, that helped me pinpoint some of the issues.

[ls_stag]

Sounds good thanks @V28VX37 I'm a little sketchy on running it on stands, but as its 4WD, I would need to have it on stands on all 4 corners? I would love to be able to see the drivetrain running. I have a vibration issue I've been trying to eliminate for a while now and the mechanic has told me to take it to a driveline expert. I'd like to have some knowledge going in.

[V28VX37]

1 hour ago, ls_stag said:

Sounds good thanks @V28VX37 I'm a little sketchy on running it on stands, but as its 4WD, I would need to have it on stands on all 4 corners? I would love to be able to see the drivetrain running. I have a vibration issue I've been trying to eliminate for a while now and the mechanic has told me to take it to a driveline expert. I'd like to have some knowledge going in.

Yep all four corners up for sure since it's 4WD.

I've made small adaptor blocks out of wood to allow jack stands under the sills, at the standard jacking points. This means that the suspension is fully unloaded when on the stands.

There shouldn't be any issues running your car on stands unless there's enough vibration to cause it to jump off, which is pretty unlikely. As a precaution you could have a mate with one hand on the ignition to shut it down in case anything goes astray.

[Trex]

Yep. You'll need someone inside the car regulating the clutch as it will most likely send all power to the front because the rear has no resistance.

[ls_stag]

Thanks @Trex and @V28VX37. Those wood blocks sound like a smart idea.

I might put it into 4wd diagnosis mode (pull the green plug in the kickplate) and do the 5 brake pedal stabs to force the car to run in RWD. Will do that and drive a little so that it's definitely doing it before jacking it up.

[V28VX37]

Also do the most basic test - put car in neutral and turn wheel by hand when jacked up. If there's increased resistance at a certain spot across the rotation it could be the hand brake assembly, this was one of the issues with mine. 

[Duncan]

3 hours ago, ls_stag said:

Thanks @Trex and @V28VX37. Those wood blocks sound like a smart idea.

I might put it into 4wd diagnosis mode (pull the green plug in the kickplate) and do the 5 brake pedal stabs to force the car to run in RWD. Will do that and drive a little so that it's definitely doing it before jacking it up.

Be careful, that won't remove all drive from the front wheels in a C34 (or and R33 or R34 for that matter), if you are going to do this you still need 4 wheels off the ground.

I think you might be better to take it to a competant mechanic, they do this sort of stuff all the time without a ferris bueller's day off type ending