AWD Transmission: - Gearbox behavior

rob s80 · Sep 16th, 2020, 05:11

Hi all,

Sorry for another gearbox question...

So my gearbox is 5 speed, gear tronic. I will get the exact model when I plug it into vida.

When accelerating the gearbox does that thing where it revs a lot and the car drives on while holding the high revs.
I do get smooth gear changes, I don't feel her go up into fifth at all. I believe this is somewhat normal for this car ?

The other thing it does which I'm more concerned about is if I'm driving around at slow speeds (under 40mph) , if I lift my foot off the gas pedal, the revs drop all the way down as if I've knocked it back into neutral or pressed a clutch fully in. Again it's still very smooth doing that action and on pick up again but just something that's concerning me.

Any advice on this would be great
Sorry again for another gearbox question !

Thanks !

SwissXC90 · Sep 16th, 2020, 07:21

What I see on my MY2009 XC90 with the 6 speed gearbox is the following:

When coasting with foot off the gas, and transmission in N, the ECU will hold the engine speed at 1500 RPM, ready to go back into gear and have power available as quick as possible

If I put my foot on the brake, it will drop the RPM to 700 RPM idle speed.

If in D and I coast, it will provide engine braking when going downhill, but will also not provide engine braking if coasting on the flat.

So the car is intelligently setting the torque converter / lockup and the engine speed to get the best assistance from the engine and gearbox depending on what you are currently doing.

Having the gearbox go out of gear and drop the revs to idle is a fuel conserving coasting feature. Why slow the car down through engine braking when you don't need to?

Tannaton · Sep 16th, 2020, 08:31

Hi Rob,

You will have the earlier E3 163 BHP car (black engine cover, not grey) which has the 5 speed box.

This sounds perfectly normal - on that car when in automatic mode the torque converter only locks at 55 mph in 5th. When I saw lockup I mean when the engine revs are locked to the road speed like with a manual car. If you find a quiet country road and accelerate gradually you will see when you get to 55-60 mph the engine revs fall off slightly and if you maintain than speed and lift off the throttle - they don't fall away.

Below this "lockup" threshold, the revs will fall to idle if you lift off the gas at any speed. You could try moving the gear lever over to the left and have a go in manual mode, in doing that you get lock-up in more gears and more engine braking.

It's the smoothest of all gearboxes fitted to the XC90 - I miss mine.

Tannaton · Sep 16th, 2020, 08:42

One thing I would add - if there is no history of it I would change the gearbox fluid in the near future - it's likely to be even more smooth after than...

If you're not sure of the history best to do in gradual sump dumps (search the forum for how to).

rob s80 · Sep 16th, 2020, 11:50

Perfect, I'm happy to hear this, was praying I wasnt looking at a expensive repair !

The gearbox oil change / flush will be done anyway, I do tend to look after auto gearbox's very well like that !

Thanks all ! I'm becoming incredibly happy with this car

Sep 16th, 2020, 05:11	#1
rob s80 Junior Member Last Online: Jul 7th, 2021 04:00 Join Date: Mar 2013 Location: dublin	Gearbox behavior Hi all, Sorry for another gearbox question... So my gearbox is 5 speed, gear tronic. I will get the exact model when I plug it into vida. When accelerating the gearbox does that thing where it revs a lot and the car drives on while holding the high revs. I do get smooth gear changes, I don't feel her go up into fifth at all. I believe this is somewhat normal for this car ? The other thing it does which I'm more concerned about is if I'm driving around at slow speeds (under 40mph) , if I lift my foot off the gas pedal, the revs drop all the way down as if I've knocked it back into neutral or pressed a clutch fully in. Again it's still very smooth doing that action and on pick up again but just something that's concerning me. Any advice on this would be great Sorry again for another gearbox question ! Thanks ! __________________ 2004 S80 2.0T 2008 V70 D5 SE Lux 2005 XC90 2.4 D5 SE Executive 2008 XC70 3.2 6 cylinder

Sep 16th, 2020, 07:21	#2
SwissXC90 Premier Member Last Online: Mar 20th, 2024 18:26 Join Date: Jan 2016 Location: Cross Country	What I see on my MY2009 XC90 with the 6 speed gearbox is the following: When coasting with foot off the gas, and transmission in N, the ECU will hold the engine speed at 1500 RPM, ready to go back into gear and have power available as quick as possible If I put my foot on the brake, it will drop the RPM to 700 RPM idle speed. If in D and I coast, it will provide engine braking when going downhill, but will also not provide engine braking if coasting on the flat. So the car is intelligently setting the torque converter / lockup and the engine speed to get the best assistance from the engine and gearbox depending on what you are currently doing. Having the gearbox go out of gear and drop the revs to idle is a fuel conserving coasting feature. Why slow the car down through engine braking when you don't need to? __________________ XC90 R-Design MY2009, Black Sapphire Metallic. HP-Sound, RSE, Nav, Tel, ParkingCam, BLIS, ParkingHeater, RestHeat, Removable Towbar, Summer: CRATUS 20x8 on Pirelli Scorpion Zeros 255/45, Winter: NEPTUNE 17x7 on Continental WinterContact 4x4 235/65. Last edited by SwissXC90; Sep 16th, 2020 at 09:30.

Sep 16th, 2020, 08:31	#3
Tannaton Bungling Amateur Last Online: Today 00:18 Join Date: Aug 2014 Location: Beverley, East Yorks	Hi Rob, You will have the earlier E3 163 BHP car (black engine cover, not grey) which has the 5 speed box. This sounds perfectly normal - on that car when in automatic mode the torque converter only locks at 55 mph in 5th. When I saw lockup I mean when the engine revs are locked to the road speed like with a manual car. If you find a quiet country road and accelerate gradually you will see when you get to 55-60 mph the engine revs fall off slightly and if you maintain than speed and lift off the throttle - they don't fall away. Below this "lockup" threshold, the revs will fall to idle if you lift off the gas at any speed. You could try moving the gear lever over to the left and have a go in manual mode, in doing that you get lock-up in more gears and more engine braking. It's the smoothest of all gearboxes fitted to the XC90 - I miss mine. __________________ 2011 XC90 D5 Executive 2003 C70 T5 GT 2012 Ford Ranger XL SC 1977 Triumph Spitfire 1500 1976 Massey Ferguson 135 Last edited by Tannaton; Sep 16th, 2020 at 08:33.

Sep 16th, 2020, 08:42	#4
Tannaton Bungling Amateur Last Online: Today 00:18 Join Date: Aug 2014 Location: Beverley, East Yorks	One thing I would add - if there is no history of it I would change the gearbox fluid in the near future - it's likely to be even more smooth after than... If you're not sure of the history best to do in gradual sump dumps (search the forum for how to). __________________ 2011 XC90 D5 Executive 2003 C70 T5 GT 2012 Ford Ranger XL SC 1977 Triumph Spitfire 1500 1976 Massey Ferguson 135

Sep 16th, 2020, 11:50	#5
rob s80 Junior Member Last Online: Jul 7th, 2021 04:00 Join Date: Mar 2013 Location: dublin	Perfect, I'm happy to hear this, was praying I wasnt looking at a expensive repair ! The gearbox oil change / flush will be done anyway, I do tend to look after auto gearbox's very well like that ! Thanks all ! I'm becoming incredibly happy with this car __________________ 2004 S80 2.0T 2008 V70 D5 SE Lux 2005 XC90 2.4 D5 SE Executive 2008 XC70 3.2 6 cylinder

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)