mattm
Member Since: 13 Apr 2014
Location: Aberdeenshire
Posts: 122
  
|
Im wondering what the deal is with the Torque Converter lock up?
Ive had the car a year (06 2.7 auto now 112k). I changed the ATF recently by doing Fiilos method of flushing it and used Millers millermatic ATF.
When driving the car im finding that when I take my foot off the throttle engine revs fall about 400 rpm and rise back up with re-application of throttle. I noticed this morning after setting off (1 degree so it was cold) that in the lower gears the revs would fall from about 2/2.5k rpm right back to ~800 rpm on removal of throttle.
Is this normal?
Im planning or putting in my second tube of Dr Tranny (I put the the first one in about September time BEFORE I changed the fluid.) But am now thinking perhaps it could do with the ATF filter being changed and another transfusion of ATF.
Any thoughts?
Matt
|
 6th Feb 2015 12:33 pm |
|
|
Oswiperus
D3 Decade
Member Since: 02 Apr 2010
Location: Chelmsford, Essex
Posts: 1599
|
Revs will drop right down until it warms up also will not select 6th gear until automatically until oil has warmed up. When TC is locked up my revcounter will settle back about 2oo revs when I lift off.
Stu.
|
| 6th Feb 2015 12:58 pm |
|
|
mattm
Member Since: 13 Apr 2014
Location: Aberdeenshire
Posts: 122
|
As an update:
I put in a tube of Dr Tranny yesterday and ran the engine for a bit to help mix it about.
Driving into work today I noticed that the revs were dropping off less on coasting... more like the 200 rpm drop off you alluded to rather than the 4-500 I was previously experiencing.
It was also changing more smoothly and even though I was driving briskly I got better MPG on my way to work.
So an improvement!! Its worth noting that I was not experiencing transmission shudder beforehand.
Although previously (Oct/Nov 14) I did an ATF flush and transfusion I didn't change the filter which I'm now think probably would have been a good idea.
I think later on this year I'll do another flush and change the filter too.
|
| 9th Feb 2015 7:37 am |
|
|
d.lundigan
Member Since: 15 Sep 2013
Location: Chelmsford Essex
Posts: 396
 
|
I seem to be having TC lock up problems I think, only problem is nothing to compare with. My problems seems to be when pulling out of junctions only. When pulling away from a stand still in a straight line the the auto box slips in first gear then slips in second then locks up from third on wards but if im pulling out of a junction going left or right then it can slip right up to fifth gear. I can make it lock up buy taking my foot off the gas and reapplying. Geoff has done the ATF and i have also added DR T. Im hoping its normal but it just seems odd. Also i had the ATF checked for water contamination last week and all is well.
All help and advise gratefully received 
Regards
Dave
|
| 4th Mar 2015 7:27 pm |
|
|
anglefire
Member Since: 09 Mar 2010
Location: In the Club House
Posts: 4180
|
They are quite slippy TC's in the Disco - mine behaves pretty much as you describe when pushing on from stationary. Mine has been rebuilt last year.
Mine has been remapped and has an off road IC, so does have a little more torque than standard. I have read that the gearbox ECU can be "remapped" to alter the lock up characteristics, but the ECU has to be removed and posted to (Germany I think) to get it done - so that is not going to happen. Mark.
2006, D3 SE Auto - gone but not forgotten.
2014 BMW 530d M Sport Tourer.
1977 Triumph Spitfire 1500
_________________________________________________
Disco Picture Website Here
|
| 4th Mar 2015 7:33 pm |
|
|
mattm
Member Since: 13 Apr 2014
Location: Aberdeenshire
Posts: 122
|
anglefire, I would say that that is not normal! mine has been chipped and I have a certain amount of TC slip which I have partially remedied by a autobox flush and Dr.Tranny, but does not slip nearly as much as that!
|
| 5th Mar 2015 7:01 pm |
|
|
d.lundigan
Member Since: 15 Sep 2013
Location: Chelmsford Essex
Posts: 396
|
So one says it normal and one says its not  more confused now than I was 
|
| 5th Mar 2015 11:12 pm |
|
|
|
|
Rich84
Member Since: 25 Jun 2013
Location: South Australia
Posts: 238
|
Pretty sure this is designed like this. The stall on these converters is very high. This makes it easy to drive the car smoothly and is good for off-roading since the throttle is less touchy. Drive another auto like an Audi or a BMW with the same trans but a low stall converter back to back with the Landy and you'll see what I'm talking about. Much touchier on the throttle, not much converter 'slip', whereas it's not unusual to see the LR shoot to 3000rpm+ under load with converter unlocked! The normal tradeoff for this is efficiency, but since the converter can lock up in any gear, it's efficient as well.
The main thing is, it's desirable to have the converter unlocked under acceleration so you can benefit from the torque-multiplication that converters offer naturally - the greater the speed delta between the pump and turbine, the higher the output torque! Once the car thinks you're cruising, the converter should lock up again.
For me, if I accelerate moderately off the line I notice the unlocked converter the most in 2nd and 3rd gears. You can easily feather the throttle and the tacho will wave around all over the place like a normal auto, but more accentuated because of the high stall speed of the converter. If I back off for a short length of time the trans will then believe I'm cruising and engage the converter lock up. If I nail it again, the converter stays locked until next standing start. When backshifting under heavy acceleration, the converter is always locked.
Under heavy acceleration from a standstill the converter is unlocked, but the engine speed stays well above the stall speed, so 'slipping' is not evident.
The other thing to remember is this is an adaptive transmission that is programmed to 'learn' many driveability variables based on how it is driven. Ie - if it's thrashed regularly, it'll engage the converter lockup later, change down earlier and behave more aggressively to throttle position. If driven sedately, it'll change up earlier, lock the converter up earlier and generally will not change down until you hit the 'kickdown' on the accelerator. This is probably the number 1 reason we all seem to experience different behaviour from the 6HP! 2008 RRS TDV6 - Chawton White/Black/Lined Oak - 20's, h/k, sunroof - 350K KM.
2010 Audi A6 3.0T S-Line - Phamtom Black/exclusive 2-tone valcona 184K
2000 Audi A4 avant 1.8t Q Sport - Phantom Black/black 385K KM
1990 Nissan Pintara TRX - red - lots of mods - 439K KM
|
| 6th Mar 2015 4:11 am |
|
|
DiscoJake
Member Since: 23 Aug 2013
Location: Hereford
Posts: 1429
|
^^^ good post
Always thought the box was rather 'slushy' which has been more eloquently described by the high TC lock up thanks 
|
| 6th Mar 2015 5:15 am |
|
|
