A471133

Hoping the foum can help me here, you guys have come through in the past.

To preempt the questions of "why don't you bring it to the dealer", I'm stationed in the middle of nowhere right now, nearest Chevy dealer is 2+ hours drive away. Last time I used them for a seat creaking noise, they had my car for 4 weeks and ended up replacing the entire seat since they couldn't figure out the noise.

So onto the issue: Car is 14 Z51 MT, approx 8K miles. About 500 miles ago, started to hear a "clunk/clank" type of sound from driver's rear, thought it was me going crazy, ignored it. My drive to work consists of 20mins highway, and then 5 miles of not so smooth roads. The last few weeks, the noise has increased in frequency.

Particulars on the noise: Clunk/clank, localized to driver's rear. Only happens on uneven road/bumpy roads. No noise over speed bumps or large bumps, it seems to happen only on smaller ones. Only clunks once per bump, speed of noise is not effected by vehicle speed. If both rear wheels go over the bump, no noise. Happens at low speeds <40mph. No change in the car's handling/acceleration. Doesn't matter if I'm turning or going straight, always from the driver's rear corner.


After extensive googling, I've done the following to try find the source:
-pressed down on the corners to test shocks, unable to recreate noise
-put on lift, tried to pull and move all suspension parts, unable to find looseness/unable to replicate noise. Wiggled the heck out of each wheel, no movement, no noise
-on ramps, repeated above with suspension loaded and unloaded, unable to find loose parts or noise
-changed rear sway bar end links for new ones, no change in noise
-ensured axle nuts are tight. Seems the they changed this from the C6 years, axle nut is now 36mm and staked in a groove so it is secure
-Left rear wheeliner removed, inspected the brake ducts, pump for ELSD, fuel filler appartus, no evidence of anything to cause the noise
-rear bumper removed, ensured exhaust hangers/connections tight, all wires/cables behind rear bumper secured without movement


At this point, I am at a loss of what could be making the noise. My only thought are that its a bushing in one of the control arms, the factory "lowering" bolt clanking against something, or the shock going bad.

Hoping someone can shine a light into what could be going on. This is the first car I've had with the leaf spring suspension.

beachcomber

You tried everything and more that I can think of. Hope you get this sorted out or someone can provide you assistance on what to look for.

Thank you for your service!

Zajac

I know this is an old post but I was searching for similar clunking sounds in the rear.

I think my 2015 base C7, which has been lowered on factory bolts all the way since new, is now doing the exact same thing as described. As the OP noted, it does not happen with both rear wheels going over a bump. For me, it mainly happens when making a slow left or right 90 deg turn in a neighborhood where there are water gutter/grooves perpendicular to the street at the corner intersection.

This clunking noise did not happen before with my lowered base C7 and it did not occur after I added the front/rear Z51 sway bars. It starting occurring after I switched out the rear Z51 sway bar for the thicker FE4 Mag ride rear sway bar and also added the Z51 non-mag ride shocks at all 4 corners at the same time.

I am just guessing that it has something to do with the Mag ride larger sway bar.

Ideas?

Did the OP solve this problem?

Does not occur when tracking the car.

A471133

Sorry, old post. Problem was solved. Ended up being the rear rotor on the pass side. Somehow rotor surface and rotor center mount has separated. Dealer replaced under warranty.

robertf97

Thanks for updating this, I am having the same issue and now know where to look!

Matthewstorm

theredkni463

I have no idea, i have the same symptoms as OP and have done the same things as he has. mine is just random clunking but upon inspection, my left driver side rotor (where the clunking for me was coming from) seem to have a ever so slight crack running around the rotor. im not sure if this has to do with what OP said. also, if i park my car and use only the E-brake to park, i can replicate the sound my pushing the rear driver side tire with my feet and it "clunks" loudly and same as what i am hearing during low speeds. the passenger side does not do this. im not sure why... maybe the rotors are my problem..?

theredkni463

any update OP about the rotors? im very curious on what you mean by the clunking noise came from the rotors...

Vette_17

i will check this on my car. also have a clicking noise

rrepp

I believe he's speaking about his rear brake rotors, which on 2014's and some 2015's were 2 piece rotors and there was a problem with the two piece rotors. There was a notice to gm dealers to replace two piece rotors with one piece rotors. Newer models came new with one piece brake rotors.

Thunder22

Another 4 year old thread, why does this keep happening?

Avanti

...because ometimes the same issues keep happening and search brings them up.