Jolt when releasing brake on autobox

[Djones55]

Hi, I have a 2012 Astra Elite 2.0 CDTI auto which I've had for a month.

When releasing the brake after holding at traffic lights or stop start traffic etc, the car jumps forward as if it is late in engaging drive again.

It seems to disengage drive slightly when held in D (I notice a slight change in revs and less pressure on the car to move forward), and when releasing the brake to pull away, there's a real jolt as it takes up drive, before I press on the accelerator. If I notice a slight change in revs, I will flick the car in neutral then "D" immediately and it's fine. If I'm VERY VERY light on the brake, it doesn't hold and is fine, but anything mre than featherlight pressure on the brake to hold the car will result in a jolt when releasing the brake.

I can put it in neutral, put the electronic handbrake on then select drive to pull away, but don't want to do that if in stop start traffic.

I have a 3 month warranty with the car so am keen to see if others have had the same problem, as I never had this in my previous VW auto.

Thanks, a great forum by the way.

[Rusty2009]

It sounds like the hill start assist is doing its job, which holds the brakes on on hills to help stop you rolling back.

I would suggest trying putting the handbrake on when stopped on a hill and seeing if that makes a difference, the handbrake is designed to auto release when you pull away.

If you do have an electric one make sure you double pull it up when parking to fully apply the handbrake (they are prone to rolling away otherwise).

[niteram]

I also have an automatic tourer with electric handbrake (mine is a 1.6 petrol)
the hill start assist activates after the brake pedal is pressed for more than 5 seconds (approx) and will hold the car for about 2 seconds before releasing (enough to take foot off brake pedal and back onto throttle)
This only works on hills, not on the flat - I don't have stop/start
I do feel a bit of a clonk from the back as the brake releases
sometimes when I've forgotten to release the handbrake (after the car is parked) it makes the same noise as it releases, so I guess it's just the way it releases automatically.

but I don't think this is the same as you are describing, it sounds like yours is dropping out of drive then re-engaging as you press the throttle

how many miles has your car done, I had my transmission fluid changed at 50,000 miles due to a leak (but it was very dirty) GM don't specify/reccomend a fluid change mileage as it's sealed for life!!

Rusty, I've never double pulled my h/brake switch - even on my manual car!

[Canasta]

It's supposed to drop out of drive into neutral when you brake to a stop. It's in the manual and it's to save fuel. Mine does the same. However the transitions are very gentle with my car and there is no jolt. Maybe it does need fluid replaced. Or maybe it can be recalibrated to lessen the jolt

I found this maybe it will help. Maybe not who knows. But it doesn't look like it will do any harm to try it. I think it's the right transmission for your car
https://etesupport.zendesk.com/hc/en-us/...ansmission-