This may have been discussed before, but I am a bit puzzled as to why I get a very scary noise..almost like my transmission just fell to the ground..Not sure if this normal? Every time I Back into my garage, which is on low grade incline, and I stop to readjust I get this sound..could it be my hill assist? Can not seem to turn it off..thoughts please..it is 2024 Z51,HTC..

 

It might make a noise - but I would not describe it as the tranmission falling out. More like the car is trying to move while the brakes are still on, then suddenly released .....which is exactly what happens.

If you are on a sufficient incline, and stopped fully (which I assume is what you mean by stop to readjust), the hill start assist will hold the brakes (the regular bakes, not the EPB) when you take your foot off the brake and move it to the accelerator pedal. And, it will not release the brakes until you press the throttle - at which time the car will try to go and the brakes will release. The timing is imperfect, so there is already pressure on the drivetrain before the brakes release - the noise you hear is that driveline tension releasing (if you are hearing the normal noise).

If you stop for too long ("a few minutes") it will actually apply the EPB as well. If that gets applied, it too will release when you apply throttle pressure, but that noise and transition will be little rougher.

It can't be disabled.

"When the vehicle is stopped on a grade, Hill
Start Assist (HSA) prevents the vehicle from
rolling in an unintended direction during the
transition from brake pedal release to
accelerator pedal apply. The brakes release
when the accelerator pedal is applied."

 

We could probably give you a better answer if you record the sound and post it on the site so we can hear it ourselves.

 

Sounds worse from the inside..Thoughts please

 

I usually have hill assist work when I pull into my garage going forward and it doesn't make that much noise. it appears that your hill assist has already released as the car rolls forward before you start going back and the noise occurs.

 

If you are unable to identify the source of the noise, it is best to take your Corvette to a Chevrolet dealership for a diagnosis. As they are the experts with all GM vehicles, they will be the best source for assistance. Should you need help connecting with one in your area, feel free to email us at socialmedia@gm.com with your Username and Forum title in the subject line.

 

Update on my issue with clunk sound. I had thought it only Made this noise when on a slight incline..Now I realize it doing to do with hill assist…it happens every time I am in reverse, and give it moderate gas. I get the loud clunk..I know I need to take it to dealer, but want to do some research before I do. Thanks in advance

 

Hill-Hold / I have a Slight Grade in front of my garage and if i stop as pulling into my garage it will activate Hill-Hold !!!