Clunking from the rear when going over bumps?

[29OUTLAW]

Ball joint can be bound up and "snap" loose causing this type of sound.

That's probably the noise I have. My car is greased up good and I'm just not gonna worry about it.

 

[Nyoka]

I get a little noise about 25% of the time when I take off in 1st gear with the wheel turned. Been happening since the car was new (2005 w/27,000 miles now). For years I used to think I ran over an acorn or twig or something because that's exactly what it sounds like. It's never gotten any worse and never gotten any more frequent and it doesn't seem to cause any issues so I've lived with it. My car is all stock and there's no way I'm gonna let anyone around here tear it apart just for that.

I read you. If this was just another high performance 'groan' I'd live with it. I, like most Viper owners I suspect, experience audible torque-related feedback from various areas of the car most of the time, and the much-reported intermittent power steering noise (sounds like that's what you have), but this one is reminiscent of the initial engagement sound from sloppier pinion/ring gear clearances of yore, including those from the Dana 60s that were fitted to the big block HEMIs, which I owned.

The new "speed-sensing" GKN Visco-Lok diff in the GEN IV is more complex (4 pinion gears, hydraulic clutches, etc.) and rocket science by comparison, as it was designed to provide "progressive and linear lockup characteristics". I think the "progressive...lockup" process is what I'm hearing and since it's brand new feedback (after 15,000 miles), I don't believe it's normal. From what I can gather, there aren't many reported instances of bad GEN IV diffs but they can't all be gems.

I'll be re-checking the ball joints, though.

Thanks for your input.

 

[Nyoka]

Ball joint can be bound up and "snap" loose causing this type of sound.

I'll be looking at ball joints again but am curious if you've had any occasion to replace one of the new diffs and, if so, why?

 

[Nyoka]

My '08 Coupe (15,000 miles) is in the "clunk" rather than "knock" category; reminiscent of 60's MOPAR ring gear when engaged with an auto at stall speed. It started about a month ago and is only evident at low RPM, in first gear from a dead stop and can be intermittent. It's often accompanied by a ratcheting sound/spring loading noise so my first thought is loose/badly seated shocks/coils. Worst fear is multi-clutch diff. Major annoyance as I'm reluctant to get into it for fear of leaving the rear end scattered all over the road.

Appreciate the inputs re: sway bars, frame bolts, etc., as I'm heading for the dealer this weekend to isolate the problem (before pulling the diff). Will report what we find.

Replaced driveshaft, no help. Tightened every conceivable nut and bolt, no help. Replaced the diff; problem solved. Weren't permitted to break down the old unit's clutch pak but oil had visible particulate throughout like clutch plate surface material. Half-shaft setup with 560 lb.ft. of torque = lots of strain. Still trying to get a post mortem on old unit...

 

[escapedan]

UPDATE - I am still getting a very loud knocking (cracking?) sound from the driver side rear of my 06 Coupe. Its getting worse and really starting to concern me, not to mention annoy me. To recap, this only happens when the car is warmed up, typically after driving a few miles and seems to be coming from behind the driver toward the rear of the car. It is very loud and easily (very easily) heard from both inside and outside the car. It happens at all speeds, in any gear and neutral, and is not specifically tied directly to hitting a bump in the road.

So far I have done the following:
- Removed the rear wheel well panels, rear diffuser, and belly pan
- Removed every bit of interior plastic, carpet, etc from the seats back
- Tightened every nut and bolt I could see and some that were not so easy to find
- Replaced all four shocks with take-offs from a 2008 SRT-10
- Used the larger shock bolts (see earlier posts in this thread)
- Drank heavily and banged my head on the wall repeatedly

I wont give up because its not in my nature, but its getting worse. I can reproduce the sound when the car is parked by lifting on the chassis and then pushing it back down (compressing the suspension).

Please, any suggestions? Or can anyone recommend a Viper Tech in the San Jose / San Francisco, California area? I am truly stumped.

 

[Viper Specialty]

UPDATE - I am still getting a very loud knocking (cracking?) sound from the driver side rear of my 06 Coupe. Its getting worse and really starting to concern me, not to mention annoy me. To recap, this only happens when the car is warmed up, typically after driving a few miles and seems to be coming from behind the driver toward the rear of the car. It is very loud and easily (very easily) heard from both inside and outside the car. It happens at all speeds, in any gear and neutral, and is not specifically tied directly to hitting a bump in the road.

So far I have done the following:
- Removed the rear wheel well panels, rear diffuser, and belly pan
- Removed every bit of interior plastic, carpet, etc from the seats back
- Tightened every nut and bolt I could see and some that were not so easy to find
- Replaced all four shocks with take-offs from a 2008 SRT-10
- Used the larger shock bolts (see earlier posts in this thread)
- Drank heavily and banged my head on the wall repeatedly

I wont give up because its not in my nature, but its getting worse. I can reproduce the sound when the car is parked by lifting on the chassis and then pushing it back down (compressing the suspension).

Please, any suggestions? Or can anyone recommend a Viper Tech in the San Jose / San Francisco, California area? I am truly stumped.

Sounds like it could be stress/frame/mounting related. Try to locate the area, and look for any mounting points, or brackets bolted to the frame that may "pop" from frame stress. Definitely a two-person job to locate noises like this. Also, try to nail down whether it is a frame/suspension noise, or a body/frame noise. Try lifting different areas to figure out what is being affected.

 

[escapedan]

Thanks Dan - I'm all over it tomorrow and I'll keep posting updates.

 

[escapedan]

Took the car to the Dodge dealership today - they have two Viper techs on staff. I'll post updates as I get them.

 

[escapedan]

UPDATE - Car is still at the dealership, but they think they have isolated it to a bad rear driver side ball joint. They've lubed it up and taken it for a short drive with no indication of the knocking. It's raining pretty bad here and they want to drive it for a longer period of time in dry weather to ensure the water is not acting as a "lubricant". So far, so good...fingers crossed.

 

[escapedan]

Took the car home today and drove it for about 20 minutes - no more knocking!!! It seems in my case the culprit was a bad ball joint. Time will tell, but so far so good!