TF-80SC at the lights

[passenger]

There is no way in any car I would 50x per day pull ebrake and put in N. I think they are okay in D on traffic light.

My ex 2015 kia cee'd double clutch gearbox disengaged after few seconds on brake

[Clan]

Originally Posted by bananarama

Parking brake aside, the original question is yet to be answered. Maybe we don't know?

I've been doing some testing and it's not entirely obvious if the box does or doesn't disengage after a few seconds of having the brake on.

I think the old AW70/71 used to disengage when the car stopped .

[FreshAir]

Originally Posted by Tatsfield

.......and the parking brake handles hill starts and automatically releases as the car moves away. It's the first time I've had a parking brake like this and I always smile when I use it as it seamlessly lets me pull away. Unless I haven't put on my seat belt when Nanny Volvo wags her finger at me and won't let me drive away!

The foot brake also holds for hill starts for maybe 3 seconds without the parking brake.

[sellxc70]

Originally Posted by bananarama

When in D do our auto boxes "disengage" after a period of not moving? And if they don't is it worth popping into N until you move again?

The AWTF80SC does have a neutral control when stopped and in D. Moving to neutral isn't necessary but as Clan says you can use the parking brake when stopped.

The reason for this was to stop the transmission oil temps rising when stationary in D. These transmissions are very sensitive when the oil temperature get too hot. I would go further and say that the cooling could have been improved and servicing added to the schedule . Perhaps most of the testing on the volvo range was in sweden in the cold weather?

I've have had my neutral control programmed out and would recommend this.

[apersson850]

The automatic shift to neutral at standstill was removed already in production from some date - don't know when. It has never been there on my 2012.

Volvo test cars in all climates. But some issues take years to show up, so they may not discover them during testing.
At least the oil cooler is watercooled on these models.

The fuel consumption at idle is reduced quite a bit by shifting to neutral.

Interesting to see that there's a regulation in Britain about not having the brakes applied at standstill. No such thing here. They rather think it's good that cars at standstill glow red, so you notice.

[Tatsfield]

Holding the car on the brakes can have one downside. I owned Brembo 4 pot braked cars for about 15 years and was warned that after spirited use of the brakes which heated the discs to higher temperatures, it was not advised to hold the car on the brakes as this could result in differential cooling of the discs leading to warping. The hand brakes on these particular cars were drums built into the rear discs as this avoided the potential warping of the discs. This may well not apply to my XC70 whose brakes were designed long after my previous cars ceased production.

[dhr90]

I’m curious, if the box is left in D, and the handbrake applied, will the car not then try to pull away and be creating a constant tension through the drivetrain once you release the foot brake?

[bananarama]

Originally Posted by sellxc70

The AWTF80SC does have a neutral control when stopped and in D. Moving to neutral isn't necessary but as Clan says you can use the parking brake when stopped.

The reason for this was to stop the transmission oil temps rising when stationary in D. These transmissions are very sensitive when the oil temperature get too hot. I would go further and say that the cooling could have been improved and servicing added to the schedule . Perhaps most of the testing on the volvo range was in sweden in the cold weather?

I've have had my neutral control programmed out and would recommend this.

Interesting you mention improving the cooling because an American on the swedespeed forum did it: https://www.swedespeed.com/threads/2...ng-hot.656122/

Last July I was in France and Switzerland when it was REALLY hot but didn't have the OBD scanner with me so didn't get a chance to see how hot the ATF was.

[bananarama]

Originally Posted by dhr90

I’m curious, if the box is left in D, and the handbrake applied, will the car not then try to pull away and be creating a constant tension through the drivetrain once you release the foot brake?

Exactly, this is the point I'm trying to make. Regardless of footbrake, electronic hand brake, etc etc, the box is still in D delivering torque, so unless it can pop into neutral when you haven't been moving (at the red lights or in traffic) the clutches will be wearing out, the ATF warming up, and fuel getting used.

However, this may not be an issue...

[apersson850]

Originally Posted by Tatsfield

Holding the car on the brakes can have one downside.<...> This may well not apply to my XC70 whose brakes were designed long after my previous cars ceased production.

Since the parking brakes use the same pads on the same discs, there will be no difference. Besides, when stopping for red lights or whatever you have hopefully not been driving like Ayrton Senna right before.

You have to manually select N to get rid of the car trying to get away when idling. No automatic neutral function any longer. But there's no clutch wear at standstill, since the clutches and brakes in the box are fully engaged for first gear. It's only the oil that's slipping. It's heated much more when driving, though. Especially if lockup is not active.