Member Since: 12 Jan 2015
Location: Cirencester, Glos.
Posts: 53
Gearbox flush - now have some hesitation on changes?
Had my 6 speed auto box double flushed a week ago (along with a full B service and some other bits and pieces)... i was expecting it to be lovely and smooth but now it seems like there is some hesitation on changes, especially when approaching a junction or roundabout etc.
Also the changes seem to be a bit more fierce?
Indy said best not to put in Dr Tranny at the time as no judder or symptoms beforehand.
Am i concentrating on it too hard and maybe noticing something that was always there, or have people had this before?
Cheers
20th Mar 2015 11:50 am
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
Milage?
Any issues with the box before?
Are you the only owner?
Do you tow?
Were the adaptions reset after the flush?Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 12 Jan 2015
Location: Cirencester, Glos.
Posts: 53
Hi Robbie
94k
2nd owner
no problems before and havent towed anything since ive owned it
adaptions not reset - but have spoken to the indy and he is going to do this in a couple of weeks when i take her in for my lower bushes to be changed
20th Mar 2015 11:55 am
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
Without seeing or smelling the old oil its difficult to be sure if the box was fully ok before. 94k is a reasonably high milage.
Disappointing that the adaptions were not reset and it makes me wonder what else was not done. The first thing I would check is the oil level when tested correctly at the correct gearbox temperature.
Did you check what oil he was putting into it?
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 12 Jan 2015
Location: Cirencester, Glos.
Posts: 53
Didnt check what oil...
Its CMS in Stroud - had some good reviews on here and had plenty of discos down there when i went in. He used to work for landrover for 8 years i think and now has over 20 years experience. Assumed he knows the job
20th Mar 2015 12:30 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
That's encouraging but I would still check the level at the correct temp. If it is ok then next step is adaptions reset.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
Chris@discovertrees wrote:
Question relating to the gearbox adaptions reset...
Can't find the answer anywhere! How does it work??
Once reset do you have to do a retraining procedure? Or does it just change over a set period of miles/time?
The gearbox starts with a set of assumptions based around the 'typical' performance of the gearbox. As the gearbox is used it learns what its ideal or 'best' shifts are and compares new shifts against this 'developing' ideal. Some shifts are rejected from the learning process (ie unusually bad or harsh shifts, or extremes of temperature) but the ones that are retained in memory as 'good shifts' are used to change the hydraulic pressures on the clutches so that more shifts are closer to the ideal. The 'ideal' itself is also slowly adjusted over time to cater for degrading components and degrading oil.
A typical gearbox adaptions over time look like this (ZF8 gearbox in this case):
Once reset the gearbox adaptions go back to the original datum values:
After driving for 5 to 10 miles or so you can see the new adaption values being learned for the new conditions:
Hope this helps.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 12 Jan 2015
Location: Cirencester, Glos.
Posts: 53
Thanks for replies. Very informative! And understand how it works now.
Allows me to see that no labour time is required by the Indy other than for the reset itself - I.e. No road test training procedure like what was mentioned to me...
21st Mar 2015 4:07 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
After 5 journeys over 2 days (around 120 miles of mixed town and country) my adaptions had adjusted themselves to this:
I'd expect a quick road test after any work on the gearbox, but there is no set learning procedure to be done.
In the sceenshots above you can also see the gearbox oil temp and this makes a big difference to the volume of oil in the box. The gearbox is a 'fill-to-spill' design.
Land Rover - Turning Drivers into Mechanics Since 1948
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
