Member Since: 25 Oct 2005
Location: Wiltshire
Posts: 67
Off road for the 1st time in a D3 - some questions...
I've had a Defender for the last 5 years and have good experience with it off road, manual Td5 with ABS ETC etc and about 2 thousand scratches down each side - great fun but hard work for longer journeys so the Defender has been sold.
I now have a 1000 mile old TDV6 Auto which is fabulous and I've just tried her off road for the first time on some green lanes in and around the Devils Punch Bowl in Surrey - it's unbelievably comfortable, although I am being very precious with her and wont be collecting scratches if I can avoid it.
However - I'm not convinced either 1) I understand or 2) something is not quite right with the following. Please note this is an AUTO.
OK so, steep downhill on loose shale/mud
Low Box selected successfully
Left in normal setting (didnt try out any of the Terrain settings just yet)
Used command shift to select first to try and roll her down with engine braking keeping her nice and slow.
Let off brake and let the car start to roll (feet off all pedals)
I was expecting a smooth descent with some engine braking
However I got an increase in speed followed by a sharp correction, enough to throw you forward into the seat belt a bit, then a steady acceleration... then the same again. Now I am no expert on Auto torque converters and over runs but I wasnt expecting a jolting joyride (it didnt seem very healthy for the vehicle so I braked gently to avoid the effect). Note I had hill descent OFF so this wasnt ABS chattering (tried that later on).
Further down the green lane I tried out various Terrain Response settings and all is well... I didnt get this accelerate, jolt accelerate jolt effect again but the track was not as steep again.
Advice appreciated please, especially from you folks who have spent time off road with these amazing machines. It was the very first time she has got her boots dirty so maybe I should be gentle...
I was rewarded with some very odd looks dropping down a muddy track to a packed A3 and accelerating off ! Normal smooth service resumed back on Tarmac.
(Martin thanks for a fantastic forum here !)
regards
Andy
7th Apr 2006 7:42 pm
Gareth Site Moderator
Member Since: 07 Dec 2004
Location: Bramhall
Posts: 26702
I have had this, it is the torque convertor tipping in and out. I actually think its a bug in the system, but you can overcome it by not using command shift, and engaging HDC.
Trust the auto gearbox, it is very clever and will take you down the hill correctly.
7th Apr 2006 7:47 pm
crasha
Member Since: 25 Oct 2005
Location: Wiltshire
Posts: 67
Thanks Gareth - sounds like it's not a fault then but "designed in"
It seems unusual that you cant just tickle down a slope having selected the appropriate gear in Command Shift without having to use electronic aids. Other Autos I have tried didnt have the same engine braking as say a manual in low first but they didnt exhibit kangaroo behaviour either.
If I get the chance to get to an "experience" centre I will be discussing with gusto.
Anyone else had similar experience? know how to fix or avoid it or should I stop being a luddite and let the electronics get me down as Gareth suggests (I do like putting the vehicle in the right gear and doing a slow feet off descent though - thats what 4x4s are good at)
Thanks Andy
7th Apr 2006 8:56 pm
DG Site Moderator
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50934
I'm no great expert by any means but isn't the machine designed to work at it's best via HDC - what circumstances would there be where you would not want to use HDC?
Member Since: 25 Oct 2005
Location: Wiltshire
Posts: 67
wow
Great video DickGriff... maybe I should get back out there !
My experience of HDC in a Discovery 2 was more of a "if you get it completely wrong safety cut in", otherwise a bit annoying for general descents... and if you were in the right gear it didnt need to cut in... i never missed having it in my Defender but ABS and ETC was excellent... maybe they have updated HDC somewhat for the Discovery 3.
I am still bemused why the vehicle doesnt go down smoothly just in a selected gear with limited engine breaking without any HDC or Terrain program selected. Thats means you must hit the HDC button or prepare to potentially lose control of the vehicle as it kangaroos down a slope... wouldnt want to be in the situation where I had forgotton to dial or hit the right buttons and mess it up even though I was in the right gear.
From my experience when you select Low 1st in the Command Shift and then release the brakes the D3 will travel down very steep slopes unde rengine braking very well and no brakes are needed.
Only when the track looks like you could get out of control do I use HDC. As you know you can always push HDC at any time. The reason for not using HDC all the time is that it can overheat your brakes and the ABS is unnessarily working when you don't really need it.
Chris2011 Discovery 4 (MY12) SDV6 HSE with General Grabber AT's, Traxide Aux Battery system, custom rear drawers and Autosafe half height cargo barrier
Gone - 2005 Discovery 3 TDV6 HSE
ARB Bull Bar, Warn 9.5XP Winch, IPF D/Lights, Cooper STT's, LR Raised Air Intake, Traxide aux battery system, custom drawers and half height Autosafe cargo barrier, Mitchell Bros 4x4 tow hitch
7th Apr 2006 11:23 pm
crasha
Member Since: 25 Oct 2005
Location: Wiltshire
Posts: 67
Chris - thats my previous experience too, HDC is great if needed... and looks like it was on the video above! but I am used, as you say, to going down most slopes in perfect control with the right gear selected... in my case it's not smooth at all with acceleration followed by a sudden jolt which I was not expecting... some kind of auto torque converter effect - maybe time for another play tomorrow.
regards Andy
7th Apr 2006 11:43 pm
chex
Member Since: 06 Mar 2006
Location: UK
Posts: 47
Was DSC on?
maybe thats what was causing the interference
8th Apr 2006 12:07 am
crasha
Member Since: 25 Oct 2005
Location: Wiltshire
Posts: 67
yep DSC was on, was initially just trying low box command shift then terrain and HDC settings didnt try DSC but the jolt felt like a auto gearbox something rather than any abs etc - it was quite violent shoving you into the seat belts !
8th Apr 2006 12:14 am
disco4x4au
Member Since: 19 Jan 2006
Location: Perth
Posts: 409
I've experienced exactly the same thing, in low first going down steep sand dunes with the HDC and DSC off. It was quite disconcerting, and I didn't notice it in low second. A light touch of the brake pedal seemed to stop it.
Cheers,
Gordonex - 2006 D3 TDV6 SE, silver, with lots of stuff - R.I.P.
ex - 2009 D3 TDV6 SE, silver, had lots of stuff too!
Now - 2010 RRS 3.0 TDV6, rimini red, 18" rims + Cooper LTZ, rear eLocker, Spider tuning box, GOE protection plates and rock sliders, GOE 3way shortened rods.
8th Apr 2006 2:05 am
nwoods
Member Since: 04 Apr 2006
Location: Southern California
Posts: 563
I just watched the video that was linked, and my thoughts were, Wow, they were going a lot faster than my LR3 will go on decent with HDC on.
In fact, my car will come to a stop unless I apply the throttle to keep it going.
I haven't a great deal of expereince with either mode yet, but it seems that leaving it in 1st low is the best way for non life threatening decents. HDC is a little too effective for my tastes unless it's a very technical decent with lots of pitch and camber changes with rock hazards, etc...
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50934
nwoods wrote:
I just watched the video that was linked, and my thoughts were, Wow, they were going a lot faster than my LR3 will go on decent with HDC on.
I'm not sure that you can tell from the video just how steep 'Geronimo' is.... but remember that the inertia of 2.75ton going into a vertical drop means that the vehicle will not initially be held by HDC - for the first 3-5 feet of 'Geronimo' the rear wheels are practically airborne and the HDC didn't really started to kick in until 1/2 way down the hill.
So the impreession that we we going fast at the beggining is sort of correct but believe me the technology does work to give great control as soon as it can.21 year LR veteran > D2 GS 2003 > D3 S 2006 > D3 HSE 2009 > D4 HSE 2013 > D4 HSE 2015 > D5 HSE 2018 > DS HSE R-Dynamic P300e 2021
8th Apr 2006 8:19 am
crasha
Member Since: 25 Oct 2005
Location: Wiltshire
Posts: 67
Thanks for the posts everyone.
I know HDC is a great tool for bad conditions... and hi DickGriff -your toboggan run certainly merits it !!! that looks sweaty palms fantastic fun.
I have also heard of some of the crazy antics in Utah on the Lions Back which seems like a place to stab HDC like your life depended on it !
and have some friend moving back to melbourne with an D3 habit so watch out.
I'm talking about everyday hill descending where you just want the car to tickle down a steep slope under gear with no need for the ABS to be chattering with HDC.
I did read the manual (finally!) and it does mention using the + and - keys on the steering wheel (one for cruise control) to alter the descent speed with HDS on. It also mentions using HDC all the time, so I will try that next, maybe HDC comes in before the vehicle reaches this "jolt" speed. Or maybe you have to feather the brakes.
However this still doesnt answer the question as to why the car wont go downhill smoothly in low box first, not a serious hill requiring HDC for safety just steep enough to merit some low box control.
The Auto box is fantastic generally, this is just a minor niggle that I'd like to understand and avoid.
thanks Andy
8th Apr 2006 9:29 am
Tim in Scotland
Member Since: 27 Jun 2005
Location: All at sea
Posts: 496
D3 and RRS have Mk3 HDC and if you feel that it is acting too harshly or soon you can adjust the rate of descent by pressing the cruise control + button and it will let you travel down hill more quickly and, in my limited experience on the Sport, much more smoothly. The added bonuses apart from a bit of extra speed are that the brakes get less wear (HDC operating eats discs/pads!) and also there is less whizzing and groaning from the ABS to scare the passengers. I must admit though that I prefer low 1st and no HDC/DSC for steep descents.
8th Apr 2006 9:41 am
DG Site Moderator
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50934
Crasha
Are you coming to the South East meet on 29th April???
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