Rear Thud Sound When Turning

[camguynj]

Noticed a slight thud sound coming from trunk when turning left low speed. Sounds like a ball hitting the quarter panel. 40k miles , Spohn rear trailing arms and BMR rear sway bar installed at 4K mi, QA1 rear shocks at 24k mi. Any thoughts ? Thanks

[BG-CAMARO]

same happens to me... doesn't seem to be doing any harm though just a bit annoying, I'm curious on what others have to say though.

[AlanRubin]

Put the car up in the air, rear wheels off the ground.

Push and pull the wheel at 12 & 6, then 3 & 9 and look at the lower bushing in the
knuckle, not the LCA. There should be no movement. Also, look for movement
at the top knuckle bushing for the UCA, & inner bushing on the upper LCA. These are
spherical bushings. When they go bad, they are not replaceable, per-say. If you
can find rubber or POLY bushings that fit in those positions, you can use them. The
spherical bushings simply make for better wheel track in turns and uneven road surfaces
to maintain camber angles under those conditions. Using rubber or POLY there will just
allow some camber changes as the wheel articulates.

You cannot buy the spherical bushings for the 5th gen, just the 6th gen, and they're
$600 even if they would work, and that is just for the knuckle. There is a POLY
replacement bushing for the inner UCA location. Finding ones that fit the knuckle
is the issue.

THEN, check your rear sway-bar links and bushings, they are the most common
reason for knocking noises.

[1JEWLDSSRS]

Originally Posted by AlanRubin

Put the car up in the air, rear wheels off the ground.

Push and pull the wheel at 12 & 6, then 3 & 9 and look at the lower bushing in the
knuckle, not the LCA. There should be no movement. Also, look for movement
at the top knuckle bushing for the UCA, & inner bushing on the upper LCA. These are
spherical bushings. When they go bad, they are not replaceable, per-say. If you
can find rubber or POLY bushings that fit in those positions, you can use them. The
spherical bushings simply make for better wheel track in turns and uneven road surfaces
to maintain camber angles under those conditions. Using rubber or POLY there will just
allow some camber changes as the wheel articulates.

You cannot buy the spherical bushings for the 5th gen, just the 6th gen, and they're
$600 even if they would work, and that is just for the knuckle. There is a POLY
replacement bushing for the inner UCA location. Finding ones that fit the knuckle
is the issue.

THEN, check your rear sway-bar links and bushings, they are the most common
reason for knocking noises.

Great info sir!!

[camguynj]

What he said ^^^ much appreciated! Will do. BTW do you know if any of the bushings you mentioned have grease fittings?

[wasthatacop?]

Originally Posted by AlanRubin

Put the car up in the air, rear wheels off the ground.

Push and pull the wheel at 12 & 6, then 3 & 9 and look at the lower bushing in the
knuckle, not the LCA. There should be no movement. Also, look for movement
at the top knuckle bushing for the UCA, & inner bushing on the upper LCA. These are
spherical bushings. When they go bad, they are not replaceable, per-say. If you
can find rubber or POLY bushings that fit in those positions, you can use them. The
spherical bushings simply make for better wheel track in turns and uneven road surfaces
to maintain camber angles under those conditions. Using rubber or POLY there will just
allow some camber changes as the wheel articulates.

You cannot buy the spherical bushings for the 5th gen, just the 6th gen, and they're
$600 even if they would work, and that is just for the knuckle. There is a POLY
replacement bushing for the inner UCA location. Finding ones that fit the knuckle
is the issue.

THEN, check your rear sway-bar links and bushings, they are the most common
reason for knocking noises.

...thanks, this is why I love this site. I almost feel compelled to do this, even though I am not having any problems.
PS my car has 150,000 miles and I should do this.

[1JEWLDSSRS]

Originally Posted by camguynj

What he said ^^^ much appreciated! Will do. BTW do you know if any of the bushings you mentioned have grease fittings?

I don't believe they do. They are sealed and designed to last quite a long time, depending on driving habits and weather effects.

[HOJO]

Originally Posted by 1JEWLDSSRS

I don't believe they do. They are sealed and designed to last quite a long time, depending on driving habits and weather effects.

JEWLD is correct, there are no greaseable components on ours cars unfortunately.

[1JEWLDSSRS]

Yep, it's not like the "old days" where you had to grease everything to make it last, now these parts are sealed and manufactured of way better materials to last and take the abuse that they endure. Makes our cars more enjoyable because you don't have to change so many suspension pieces if you keep the alignments and tire pressures where they should be, and don't hit speed bumps at 50 mph.. lol.

[2ndtimess]

#PI0137D: Rear Axle Chatter or Moan Type Noise on Low Speed Turns (Excluding ZL1) - (Jun 28, 2013)
Subject: Rear Axle Chatter or Moan Type Noise on Low Speed Turns (Excluding ZL1)

Models: 2010-2014 Chevrolet Camaro (Excluding ZL1)Equipped with Limited-Slip Differential (RPO G80)
Attention: For 2010 and 2011 vehicles built prior to August 25, 2010, if the chatter noise you are experiencing occurs only in Reverse while making a turn, please review the latest version of PIC5424. This PI has been revised to add the 2013-2014 model years and update the Warranty Information. Please discard PI0137C.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/ConcernSome customers may comment on a chatter or moan type noise from the rear of the vehicle while making low speed turns.
This condition may be caused by a slip/stick of the posi-traction clutch plates. As the plates slip and stick, a jumping or jerking feel occurs, accompanied by a chatter noise.
Recommendation/InstructionsCaution: The rear axle seals must be replaced. The original seals are not compatible with the new fluid.

Replace both rear axle shaft seals with GM P/N 22798805 and drain/refill the rear differential with new fluid, GM P/N 88862624 (in Canada, use P/N 88862625). Refer to the Rear Axle Shaft Seal and Differential Oil Replacement procedures in SI. This fluid includes a limited-slip additive (friction modifier) already added. DO NOT add any limited-slip additive (friction modifier).
Important: Please advise the customer that once the differential fluid has been changed, it may take as long as 805 km (500 miles) for the lubricant to fully penetrate the limited slip clutch plates. During this period some chatter may still be felt on initial startup while making slow turns until the rear differential fluid warms up.

Note: DO NOT re-use the wheel drive shaft nut. Replace with NEW only.

[AlanRubin]

Originally Posted by camguynj

What he said ^^^ much appreciated! Will do. BTW do you know if any of the bushings you mentioned have grease fittings?

No, none at all. Some aftermarket parts do, but never in the knuckle.

Most MOOG parts have zerk fittings, but not the LCAs, because I have MOOG
rear LCAs. I had greaseable front LCAs. You can get tie-rod ends that
also have them.

However, nothing I have REAR has zerk fittings. I have a needle injector
that I can fit between the boot and metal post on ball joints to shoot some
in before installation.

[camguynj]

Originally Posted by camguynj

Noticed a slight thud sound coming from trunk when turning left low speed. Sounds like a ball hitting the quarter panel. 40k miles , Spohn rear trailing arms and BMR rear sway bar installed at 4K mi, QA1 rear shocks at 24k mi. Any thoughts ? Thanks

UPDATE - Turned out that one of the driver side rear sway bracket bolts backed out (actually fell out) ...probably wasn't torqued to spec when it was installed which caused the bracket to bend so I replaced it, put a litte blue loctite on and made sure it was torqued to spec.
All good

[1JEWLDSSRS]

Originally Posted by camguynj

UPDATE - Turned out that one of the driver side rear sway bracket bolts backed out (actually fell out) ...probably wasn't torqued to spec when it was installed which caused the bracket to bend so I replaced it, put a litte blue loctite on and made sure it was torqued to spec.
All good

Awesome find bro!! Thanks for coming back and letting us know what it was..

[gilbert85295]

I was getting the same noise. I finally buried the body that was in the trunk and it stopped. Go figure.