G6 Rear Suspension

[cp3]

The wife's G6 has developed a "clunk" in the rear suspension over sharp bumps. It has also started to feel "loose" (as in the racing term) while going around on ramps. As you are going around the ramp, about mid way through it feels like the back end shifts to the outside of the turn.

At first I thought maybe the winter tires with their smaller rim and higher aspect ratio might be to blame and we just didn't notice it before. It is less pronounced now with the summer tires back on but still there, the feeling, sound never changed.

I'm thinking shocks. This car also has an upper shock mount and I am suspecting this for the noise.

Any other suggestions or ideas?

 

[CharlieJ]

Check the rear sway bar endlinks. I have a much stiffer aftermarket rear sway bar on my Mazda3 that would loosen and "clunk" over bumps. I put on some washers and tightened it down and have not had a problem sense.

 

[NHGUY]

Some GMs have a flimsy trailing arm (folded narrow sheet steel) that rusts out and when it snaps the wheel is not located solidly at all.I believe its just W bodies that suffer this design fault,dont know about G6.

 

[cp3]

The end link feel tight and the trailing arm is a solid piece, definitely not broken at least. The only folded piece seems to be the aluminum lower control arm. I was under there today as I have to order some other stuff and want to get it all at once. Of course I can't duplicate the noise in the driveway. Never seen a shock mount before, guess that's why I figure it's making the noise.

Speaking of the links are the front links supposed to be solid? These are type with the ball joints on the ends. The G5s are rattling and the G6 has the same part number, I can move them but no noise. Wondering if I should just do them too.

 

[artificialist]

Originally Posted By: cp3
The end link feel tight and the trailing arm is a solid piece, definitely not broken at least. The only folded piece seems to be the aluminum lower control arm. I was under there today as I have to order some other stuff and want to get it all at once. Of course I can't duplicate the noise in the driveway. Never seen a shock mount before, guess that's why I figure it's making the noise.

Speaking of the links are the front links supposed to be solid? These are type with the ball joints on the ends. The G5s are rattling and the G6 has the same part number, I can move them but no noise. Wondering if I should just do them too.

If it moves, replace them. If they aren't making bad noises now, they will make bad noises soon.

As for noise from the rear suspension, pry against the bushings and check for movement. It should take considerable effort to move a bushing 1/4 of an inch. If it doesn't, replace that part. You would benefit from aligning the wheels after replacing the failed part.

Another thing caused a noise from the rear suspension from my dad's Pontiac G6. The fastener that held the e-brake cable to the rear suspension loosened up, and had to be re-tightened.

 

[cp3]

Ok, I will check that when I'm under there but I've already got the shocks and mounts on the way. And I did order the links for both cars. I'll keep my fingers crossed.

 

[cp3]

Well got my boxes-o-parts today from RockAuto!

Fairly confident that the shock mount is going to be the culprit for the noise. A mostly rubber piece that must degrade over a couple hundred thousand kilometers. The ball joints on the end-links are un-movable so I am happy that I ordered the pair for the G6 as well. And all of the joints are zerked!

Now when replacing suspension parts is it best to do this with the suspension loaded or unloaded? I am pretty sure I can get most if not all of this done with the car on the ramps as opposed to jacked but which is better?

 

[JosephHarmon]

Lesser cost causes would be ASB links or bushings,
You may have a caliper pins loose.
Inspect the upper shock mounts.
A loose wheel bearing may be an issue.
The knuckles have bushings that may fail.