Autobox issue on ZTT CDTi

Mills2009 · 13th August 2010, 20:13

Has anyone experienced the autobox not changing up a gear when you think it should, or lift off the throttle slightly to encourage it to change up? Its as if the gear selector is set in '3' or '2' rather than 'D'

It occurs mainly in 2nd gear or occasionally 3rd and is predominently at lower speeds as you have turned at a junction or going up a slight incline. It has been an occasional thing, but is happening a little more often now, and on flat roads too. The car is five years old and I was planning a fluid change. Any thoughts?

matt1301 · 13th August 2010, 20:18

I think fluid is due 4 Years and/or 60k so that might be a good move.

Mills2009 · 13th August 2010, 20:25

Am hoping the fluid change will sort it, was in the pipeline to do this year even before the problem started. The car has only done 35k, but I thought I should get it done on age grounds! Just wondered whether anyone else had encountered it and if a fluid change did indeed sort it?

David3807 · 13th August 2010, 21:30

Have encountered the same on both mine in exactly same circumstances - junction and then away up a slight hill. Normally only happens with a cold or coldish car ie when the autobox fluid is not up to working temp and when I have not had to come to a dead stand at the junction. Accelerating a bit harder up the incline makes the box change up.

I have put it down to the cold start proceedures whereby the car will hang on to lower gears more than usual until fluid is up to temp as a design feature in the autobox software.

Both my cars had autobox fluid changed about 2 years ago and exibited the behaviour above both before and after. On that basis not sure if a change of fluid would help you.

But as your car is 5 years old I would suggest a fluid change anyway. Fluid changes are scheduled for 60k miles or 4 years whichever sooner.

Starman · 13th August 2010, 21:45

Howdee. A fluid change is always worth doing so long as it's done properly. Just had mine done and it's loads better.

As stated the cold oil will make the gears hang promoting a quicker warm up. As opposite the warm oil will make a quicker change up to increase cooling.

Also don't forget our autos have tilt sensors on them so they will plum for holding lower gears on an incline or decline. A touch of the brakes on a descent will make the car select the next gear up.

Both mine hang the gears occasionally.
Makes you want to wiggle the selector about.

David3807 · 13th August 2010, 22:02

Quote:

Originally Posted by Starman

Also don't forget our autos have tilt sensors on them so they will plum for holding lower gears on an incline or decline.

Slightly off topic but I have always wondered if there are tilt sensors since I thought the autobox worked out what to do by accelerator position, engine and road speed, amount of steady brake pressure etc.

Mills2009 · 16th August 2010, 19:17

Good to know a few other members have experienced a similar thing. I've never really noticed it on my petrol auto, but it did hold onto 2nd going down a hill when cold on Sunday! Its gearbox fluid was changed a couple of months ago. The ZT is lined up to be done in the next couple of weeks.

13th August 2010, 20:13	#1
Mills2009 Avid contributor 1999 75 Auto & 2005 ZT-T Auto Join Date: May 2009 Location: Gloucestershire Posts: 187 Thanks: 6 Thanked 9 Times in 7 Posts	Autobox issue on ZTT CDTi Has anyone experienced the autobox not changing up a gear when you think it should, or lift off the throttle slightly to encourage it to change up? Its as if the gear selector is set in '3' or '2' rather than 'D' It occurs mainly in 2nd gear or occasionally 3rd and is predominently at lower speeds as you have turned at a junction or going up a slight incline. It has been an occasional thing, but is happening a little more often now, and on flat roads too. The car is five years old and I was planning a fluid change. Any thoughts?

13th August 2010, 21:45	#5
Starman Posted a thing or two 03 CDTi Tourer Conn SE auto Join Date: Jul 2007 Location: Shrewsbury Posts: 1,405 Thanks: 0 Thanked 15 Times in 4 Posts	Howdee. A fluid change is always worth doing so long as it's done properly. Just had mine done and it's loads better. As stated the cold oil will make the gears hang promoting a quicker warm up. As opposite the warm oil will make a quicker change up to increase cooling. Also don't forget our autos have tilt sensors on them so they will plum for holding lower gears on an incline or decline. A touch of the brakes on a descent will make the car select the next gear up. Both mine hang the gears occasionally. Makes you want to wiggle the selector about. __________________ [SIGPIC][/SIGPIC]

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13th August 2010, 20:18	#2
matt1301 Avid contributor 75 Cdti Auto Join Date: Dec 2009 Location: Bishops Stortford, Hertfordshire Posts: 151 Thanks: 1 Thanked 3 Times in 3 Posts	I think fluid is due 4 Years and/or 60k so that might be a good move.

13th August 2010, 20:25	#3
Mills2009 Avid contributor 1999 75 Auto & 2005 ZT-T Auto Join Date: May 2009 Location: Gloucestershire Posts: 187 Thanks: 6 Thanked 9 Times in 7 Posts	Am hoping the fluid change will sort it, was in the pipeline to do this year even before the problem started. The car has only done 35k, but I thought I should get it done on age grounds! Just wondered whether anyone else had encountered it and if a fluid change did indeed sort it?

13th August 2010, 21:30	#4
David3807 Posted a thing or two 2002 R75 Conn SE 2.5l Auto Tourer, 2001 R75 Conn SE 2.5 Auto Saloon Join Date: Nov 2006 Location: Gravesend Posts: 1,897 Thanks: 0 Thanked 2 Times in 2 Posts	Have encountered the same on both mine in exactly same circumstances - junction and then away up a slight hill. Normally only happens with a cold or coldish car ie when the autobox fluid is not up to working temp and when I have not had to come to a dead stand at the junction. Accelerating a bit harder up the incline makes the box change up. I have put it down to the cold start proceedures whereby the car will hang on to lower gears more than usual until fluid is up to temp as a design feature in the autobox software. Both my cars had autobox fluid changed about 2 years ago and exibited the behaviour above both before and after. On that basis not sure if a change of fluid would help you. But as your car is 5 years old I would suggest a fluid change anyway. Fluid changes are scheduled for 60k miles or 4 years whichever sooner.

16th August 2010, 19:17	#7
Mills2009 Avid contributor 1999 75 Auto & 2005 ZT-T Auto Join Date: May 2009 Location: Gloucestershire Posts: 187 Thanks: 6 Thanked 9 Times in 7 Posts	Good to know a few other members have experienced a similar thing. I've never really noticed it on my petrol auto, but it did hold onto 2nd going down a hill when cold on Sunday! Its gearbox fluid was changed a couple of months ago. The ZT is lined up to be done in the next couple of weeks.