[saabarch]

I did not see this topic posted here; if so, my apologies.

my 1LE will make a distinct pop sound, though only once, in reverse gear, putting a load on it to leave the driveway.

seems to disappear when warm.

most likely the differential. maybe the clutch packs (we have these, correct?) pinion gear, I simply don't know.

I am aware of the fluid change ( I have 2400 miles on the car) that needs to be performed.

I am also aware of the countless diff issues with GM.

I am taking it to the dealer next week to have this looked at, and will let you all know what they say.

If anyone has had this, please let us know. Only in reverse, so far. Not turning, not in forward gears. Just reverse.

[saabarch]

so first, it seems no one else has this issue.

secondly, the dealer heard the pop, says it is very odd, but cannot determine exactly where the noise is coming from, and thus cannot diagnose the issue.

the dealership was excellent by the way. i just wished they could have found the source of the problem.

in summary: i have a brand new car that makes a very concerning improper mechanical noise emanating from the rear somewhere, and nothing can be done. too bad.

well, at least i have it on the radar for chevy, so if something catastrophic happens, it will not be a surprise to anyone.

[TEX1LE]

I just had this happen for the first time this morning while backing out of the garage it was pretty loud. I have about 1500 miles on it. I guess since the dealership couldn't find the cause for you I won't waste my time going up there unless it continues to happen.

[AZ_1LE]

Funny, I just started hearing the same exact noise a few weeks ago, I have about 2300 miles on mine.

Also something I noticed coming from what I think is the rear diff - took a 2 hour drive to Tucson a few weeks ago from Phoenix where the speed limit is 75 for most of the drive. I had cruise set to 85 and after about 30 minutes, I started to hear this strange "screeching" noise coming from what I'm pretty sure was the rear end. What was odd was that it would go away if I gave it a little more gas, but would get extra loud if I let off the gas and was coasting. It sort of sounded like dragging the pointy end of a dinner fork across a sheet of aluminum, very high pitched, and pretty annoying. It started to concern me at one point. After getting home I flushed the rear diff fluid with new GM fluid, but I haven't had a chance to take it on a long cruise like that again.

[saabarch]

guys, thanks for posting. now i know i'm not going crazy.
from your two posts, it sounds like the diff.

i was hoping Chevy customer service would jump in here and give us a suggestion.

[saabarch]

since we all have the same diff as the ZL1 (yes?), i wonder if those guys are having
similar issues?

i browsed their section quickly last night but did not turn up anything.

[DenverTaco07]

Have you guys changed Diff fluid?

I have 5500 miles no issues.

does it happen sitting still and merely putting it in reverse, or does it occur as you start rolling backwards?

Brakes sticking?

If happens sitting still I doubt it would be the differential, I'd think more likely clutch plate or something. If when starting to move, Diff, Shaft, transmission, brakes all possible.

[saabarch]

not brakes as far as i can tell. not even parking brakes. i mentioned in my first post, it's when a load
is applied, in reverse gear. When you leave your garage in the
morning, for example. just when you start to roll backwards--POP! that's why i think it might be diff.
but i hear you, could be trans or driveshaft--who knows? you think the dealer or
manufacturer could tell us.

Chevy, are you monitoring these highly insightful posts? Yes? Then please let us know
what to do--thanks!

[DenverTaco07]

Originally Posted by saabarch

not brakes as far as i can tell. not even parking brakes. i mentioned in my first post, it's when a load
is applied, in reverse gear. When you leave your garage in the
morning, for example. just when you start to roll backwards--POP! that's why i think it might be diff.
but i hear you, could be trans or driveshaft--who knows? you think the dealer or
manufacturer could tell us.

Chevy, are you monitoring these highly insightful posts? Yes? Then please let us know
what to do--thanks!

ok, is it possible you can roll backwards without putting it gear and see if you get the same noise or not?

[zx9rmal]

Possible this could be parking brake sticking?

[Th3Beast]

I feel like this is the brake pads releasing from being wet. It's been raining so much here the last two weeks and last week after driving home in the rain, I go back the car out of the garage and I almost stalled the car in reverse trying to back out. The pads were so stuck that it took me actually pressing the gas to get them loose. The loud pop that was associated with that was insane.

Maybe your's is just a mild version? What about backing your car into your garage and seeing if it does it going forward as well?

[saabarch]

tried everything you guys mention with the brakes.
it nearly feels like after you wash your car and park with brake on. then
leave the next morning, and you have to break the rust--that FEELING--but
this is not it.
as i mentioned, only happens in reverse, and only once after cool down.
i grew up working on cars and have pretty solid knowledge of mechanics--this
befuddles me, as it has the dealer. if it's not the diff, then it is a swaybar
link(i have read ZL1 owners are having trouble with poorly torqued bolts)
but then that would happen all the time, correct?

Chevy--where are you?

[saabarch]

to be clear, i don't use the parking brake at home. so it's not that.

[saabarch]

by the way, thank you guys for all of your input--and if anyone else
has the same issue, please let us know! thanks again