A8 Z06- not going into reverse immediately sometimes, cracking noise follows
07-29-2018, 09:38 PM
#1
A8 Z06- not going into reverse immediately sometimes, cracking noise follows
Howdy y’all.
Been having this issue, three times over the past five weeks, googled and nothing really came up. Car is a 2016 automatic with just over 3000 miles. A year ago the rear diff was replaced, not sure if there’s any relation but putting it up here anyways.
This has also always happened in my garage, car is parked all the way up front so shifting into drive isn’t an option for troubleshooting purposes unless I wanna pay for body work (spoiler alert: I don’t!). So, what happens is I start the car and put it into reverse. Trans feels like it engages, but won’t actually go anywhere. I rev it up a bit and usually nothing. Second try I do the same and there’s a loud “crack” sound and car starts moving like normal. I can’t say for certain it’s the brakes, but both the sound and “feel” I’m guessing it’s the brakes and not something from the rear end. Yes, I made sure parking brake is off- even engaged it and disengaged it.
Any thoughts on what may be going on? I’ll eventually take it to the dealer but I’m 90% sure they’ll say if they can’t reproduce it they can’t fix it.
Been having this issue, three times over the past five weeks, googled and nothing really came up. Car is a 2016 automatic with just over 3000 miles. A year ago the rear diff was replaced, not sure if there’s any relation but putting it up here anyways.
This has also always happened in my garage, car is parked all the way up front so shifting into drive isn’t an option for troubleshooting purposes unless I wanna pay for body work (spoiler alert: I don’t!). So, what happens is I start the car and put it into reverse. Trans feels like it engages, but won’t actually go anywhere. I rev it up a bit and usually nothing. Second try I do the same and there’s a loud “crack” sound and car starts moving like normal. I can’t say for certain it’s the brakes, but both the sound and “feel” I’m guessing it’s the brakes and not something from the rear end. Yes, I made sure parking brake is off- even engaged it and disengaged it.
Any thoughts on what may be going on? I’ll eventually take it to the dealer but I’m 90% sure they’ll say if they can’t reproduce it they can’t fix it.
07-29-2018, 11:41 PM
#3
JohnH on here was telling me a lot of the earlier year cars like yours and mine do this. My personal car which is a 16 has not done it, but i pointed out to him that I always start my car using the fob, a good 30 sec before i jump in it...
he went on to explain THAT IS the solution, the car needs a chance to warm up. Obviously the torque converter or something is faulty i believe he said... but if you dont want to go through the pain of getting it replaced just yet... start your car in advance. If it was me, i would get it replaced before the bumper to bumper warranty expires on your car. Granted, it is powertrain, but you never know what they might try to bill you for if you are past the b2b.
he went on to explain THAT IS the solution, the car needs a chance to warm up. Obviously the torque converter or something is faulty i believe he said... but if you dont want to go through the pain of getting it replaced just yet... start your car in advance. If it was me, i would get it replaced before the bumper to bumper warranty expires on your car. Granted, it is powertrain, but you never know what they might try to bill you for if you are past the b2b.
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Krazy (07-30-2018)
07-29-2018, 11:52 PM
#4
JohnH on here was telling me a lot of the earlier year cars like yours and mine do this. My personal car which is a 16 has not done it, but i pointed out to him that I always start my car using the fob, a good 30 sec before i jump in it...
he went on to explain THAT IS the solution, the car needs a chance to warm up. Obviously the torque converter or something is faulty i believe he said... but if you dont want to go through the pain of getting it replaced just yet... start your car in advance. If it was me, i would get it replaced before the bumper to bumper warranty expires on your car. Granted, it is powertrain, but you never know what they might try to bill you for if you are past the b2b.
he went on to explain THAT IS the solution, the car needs a chance to warm up. Obviously the torque converter or something is faulty i believe he said... but if you dont want to go through the pain of getting it replaced just yet... start your car in advance. If it was me, i would get it replaced before the bumper to bumper warranty expires on your car. Granted, it is powertrain, but you never know what they might try to bill you for if you are past the b2b.
Next tome it happens I’m gonna get video of it- hopefully from two angles. Or hopefully whatever is the issue it just shuts the car down completely instead of being intermittent.
For now I’ll monitor as-is, but will take it in later this summer sometime. I need to get it documented in case of future failure. Have just over a year on the basic warranty plus the powertrain warranty.
Wanted to do some slight mods for the car after I got it (headers, pulley, tune) and glad I didn’t. Needed to use the warranty multiple times already. Love the car but losing faith in it. :|
07-30-2018, 12:08 AM
#5
By the 3000 mile mark, i was positive, i was leaving this thing bone stock I have been in the shop more times than you could imagine.The dealership takes pictures of my engine bay and underneath my car every time it is in, trying to prove i modify it... its comical.
The most recent visit, when i was getting my wheel insurance to cover my new wheels, i come back to see my hood is open... im like... what are you guys doing? They are like "taking pictures of your engine bay"
they aren't even ashamed.
Leave your car stock
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Krazy (07-30-2018)
07-30-2018, 12:36 AM
#6
i think they installed the rear diff incorrectly.. and it is seizing somehow. Maybe it lacks oil? lol, i have no idea, but i see what you are saying.
Could even be something seizing in the rear part of the torque tube, a misalignment when they put it all back together, or again.. something lacks proper grease or oil... and is seizing after you park it for a while.
When it happens, is it usually after the car has been sitting for a few days, or can it happen an hour after you park it and jump back in?
To replicate it... tell the dealer to park it, nose first, into a parking spot... and wait a couple days, and then start it up and try to reverse.
Also, next time it happens, put your phone on video record, and slide it on the ground so it is between the 2 rear wheels, pointing up.
You will get the noise on tape very well that way, and most smartphones record in stereo these days, so it might even help the mechanics figure out which way the noise is coming from. Granted, you will have to download the video to facebook or something so you can view it with a computer and figure out which speaker the noise comes from the most, if it is able to be heard directionally.
Could even be something seizing in the rear part of the torque tube, a misalignment when they put it all back together, or again.. something lacks proper grease or oil... and is seizing after you park it for a while.
When it happens, is it usually after the car has been sitting for a few days, or can it happen an hour after you park it and jump back in?
To replicate it... tell the dealer to park it, nose first, into a parking spot... and wait a couple days, and then start it up and try to reverse.
Also, next time it happens, put your phone on video record, and slide it on the ground so it is between the 2 rear wheels, pointing up.
You will get the noise on tape very well that way, and most smartphones record in stereo these days, so it might even help the mechanics figure out which way the noise is coming from. Granted, you will have to download the video to facebook or something so you can view it with a computer and figure out which speaker the noise comes from the most, if it is able to be heard directionally.
Last edited by Mikec7z; 07-30-2018 at 12:43 AM.
07-30-2018, 12:44 AM
#7
Race Director
You said it's happened 3 times over the past 5 weeks. Those times, was the car put away after washing the car or after a rain? If the brakes are wet and the car put away, the next time the car is put in gear, the brakes will grab and it will be hard to move the car.
07-30-2018, 12:48 AM
#8
i agree with what he said, especially if you DO use your parking brake when you park it, which I do not. I don't experience this ever with my vette, but cars that have the parking brake on, i have had this happen before when I got in and tried to take off, even tho the brake is disengaged, it is rusted in place until you loosen it. He is probably right.
Last edited by Mikec7z; 07-30-2018 at 12:49 AM.
07-30-2018, 12:54 AM
#9
i think they installed the rear diff incorrectly.. and it is seizing somehow. Maybe it lacks oil? lol, i have no idea, but i see what you are saying.
Could even be something seizing in the rear part of the torque tube, a misalignment when they put it all back together, or again.. something lacks proper grease or oil... and is seizing after you park it for a while.
When it happens, is it usually after the car has been sitting for a few days, or can it happen an hour after you park it and jump back in?
To replicate it... tell the dealer to park it, nose first, into a parking spot... and wait a couple days, and then start it up and try to reverse.
Also, next time it happens, put your phone on video record, and slide it on the ground so it is between the 2 rear wheels, pointing up.
You will get the noise on tape very well that way, and most smartphones record in stereo these days, so it might even help the mechanics figure out which way the noise is coming from. Granted, you will have to download the video to facebook or something so you can view it with a computer and figure out which speaker the noise comes from the most, if it is able to be heard directionally.
Could even be something seizing in the rear part of the torque tube, a misalignment when they put it all back together, or again.. something lacks proper grease or oil... and is seizing after you park it for a while.
When it happens, is it usually after the car has been sitting for a few days, or can it happen an hour after you park it and jump back in?
To replicate it... tell the dealer to park it, nose first, into a parking spot... and wait a couple days, and then start it up and try to reverse.
Also, next time it happens, put your phone on video record, and slide it on the ground so it is between the 2 rear wheels, pointing up.
You will get the noise on tape very well that way, and most smartphones record in stereo these days, so it might even help the mechanics figure out which way the noise is coming from. Granted, you will have to download the video to facebook or something so you can view it with a computer and figure out which speaker the noise comes from the most, if it is able to be heard directionally.
Thanks for the replies everyone.
Last edited by Krazy; 07-30-2018 at 12:57 AM.
07-30-2018, 12:58 AM
#10
yeah, 383vett is right then. You don't have anything wrong with your car i don't believe. Again, if you hit the parking brake by accident, that would really solidify the problem into occurring... vs if you dont have it on at all.
07-30-2018, 07:55 AM
#11
383 nailed it and it isn't even necessary to wash your car or drive it in the rain for this to happen. A change in the weather causing a sudden increase in temperature on a humid day will cause moisture to precipitate out on cold parts of your car that are slower to warm up than the air and this can be enough to create the slight corrosion buildup between the pads and rotor needed to create this "stuck then bang" situation. But it is a good idea to dry those brakes properly after washing or driving in the rain; when I drive any of my vehicles in the rain I drag the brakes a bit coming up the driveway to heat them up and help them dry. My Z06 brakes have never had this issue but several times I had the pads stick on my 2006 GMC 2500HD after high moisture conditions and its 2018 replacement has much more swept area so I will be extremely careful with it to dry it after rain or washing.
When it is primarily the rear brakes stuck you can usually easily "rock" out of the corrosion using the same technique you would to work yourself loose from snow but the front tires may just drag if those brakes are stuck. Shortly after the C7 generation came out a new owner called a tow truck because of some "major mechanical failure" preventing the C7 from moving. Because of the owner's location in a tight apartment parking garage the tow operator had to pull the vehicle backwards out of its slot to prep it for a longer tow and it left 5 foot streaks from the front tires until both broke loose curing the "major mechanical failure" and the owner drove his car back into its slot.
When it is primarily the rear brakes stuck you can usually easily "rock" out of the corrosion using the same technique you would to work yourself loose from snow but the front tires may just drag if those brakes are stuck. Shortly after the C7 generation came out a new owner called a tow truck because of some "major mechanical failure" preventing the C7 from moving. Because of the owner's location in a tight apartment parking garage the tow operator had to pull the vehicle backwards out of its slot to prep it for a longer tow and it left 5 foot streaks from the front tires until both broke loose curing the "major mechanical failure" and the owner drove his car back into its slot.
07-30-2018, 11:14 AM
#12
OK, that seems plausible but in nearly two years of ownership this hasn't happened until mid-ish June, and now it's happened three times. Twice wasn't after rain or after a wash, and I store the car in winters and never experienced it. Never had it happen with any other cars I've had either.
Hope that's all it is, I can live with it then. The loud "CRACK!" is kind of un-nerving though.
I appreciate the replies gents.
EDIT: I may try to use the parking brake all the time from now on. Hopefully that'll take care of it. Will bring it up to the dealer though next time I'm there to at least have it recognized in case there's more going on.
Hope that's all it is, I can live with it then. The loud "CRACK!" is kind of un-nerving though.
I appreciate the replies gents.
EDIT: I may try to use the parking brake all the time from now on. Hopefully that'll take care of it. Will bring it up to the dealer though next time I'm there to at least have it recognized in case there's more going on.
Last edited by Krazy; 07-30-2018 at 11:17 AM.
07-30-2018, 03:21 PM
#13
^^^ This happened to me twice after washing the car and storing it before I figured it out. Now after I wash the car I either drive it a couple miles or blow the wheels and brake assembly with my leaf blower it actually works LOL.
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Krazy (07-30-2018)
07-30-2018, 03:43 PM
#14
My neighbors probably think I'm an idiot.
07-30-2018, 03:52 PM
#15
Le Mans Master
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It can happen to any of my cars, not only after being washed, but also when parked in a high humidity environment for a bit (which will induce rust and corrosion on a brake disk).