Thread: Does HDC work if car stalled?

Originally Posted by Discodicky

I realise that it is preferential to switch off DSC when sand driving but I am interested why do you do it for hilly country, and also why do you switch HDC off and on all the time?
Can't you just leave it on to simplify matters?
I've not done serious 4WDing with my D4 so am very interested in people's driving mode choices.

I will leave DieselLSE to answer for himself but for me, DSC if it comes on at the wrong time it will cut power if it detects sideways movement so I leave it off - noting that the car will override this 'DSC Off" setting in extreme circumstances like too much power.

As far as HDC is concerned - in extreme damp steep conditions I do use HDC just to be safe. If you leave HDC on and you are going relatively slow, if you take your foot off the throttle the HDC may very well activate and bring you to a screaming halt pretty quick - a bit disconcerting. So I normally have it off as indicated above - but in tight technical sections particularly going up steep hills I might have it on. You really dont want a runaway backwards if you stuff things up.

So like most settings there is a time to use and a time not to use and everyone has their own preferences - there is not one answer.

Originally Posted by Discodicky

I realise that it is preferential to switch off DSC when sand driving but I am interested why do you do it for hilly country, and also why do you switch HDC off and on all the time?
Can't you just leave it on to simplify matters?
I've not done serious 4WDing with my D4 so am very interested in people's driving mode choices.

DSC: There's been a few occasions where the engine seemed to "die" for no apparent reason. Remember that hilly country still has patches of loose surface like dust, shale, little rocks etc., plus snow and clay and whatever. I just don't need the car thinking that I'm about to go careening off in a slide when all I'm really doing is preparing for the terrain a few metres in front.
HDC: If the car thinks you are driving too fast it applies the brakes. In hilly low range country you often get little dips that you are happy to let the car run on into (maybe flick it up into 4th or 5th) as you can see that a rise is a few metres ahead and the path is smooth. Or you crest a washout and face a steep immediate descent of a metre or two. In such cases, whilst you can see and adjust to what's ahead, the reactive HDC can't and wants to pull you up. The system is very heavy on discs and pads and, as 101RRS says, you just don't need it: low range with a locked torque converter and diesel engine braking ('though I admit I'm not sure if this is actually a factor anymore with modern engine management) does a perfect job on the steepest of declines. You can set the speed at which HDC operates and you can do it on the fly but I've never bothered playing with it I must admit.

FYI, I find that on most inclines, third low is my preferred gear, allowing me to shift up and down as appropriate.

Originally Posted by DieselLSE

DSC: There's been a few occasions where the engine seemed to "die" for no apparent reason. Remember that hilly country still has patches of loose surface like dust, shale, little rocks etc., plus snow and clay and whatever. I just don't need the car thinking that I'm about to go careening off in a slide when all I'm really doing is preparing for the terrain a few metres in front.
HDC: If the car thinks you are driving too fast it applies the brakes. In hilly low range country you often get little dips that you are happy to let the car run on into (maybe flick it up into 4th or 5th) as you can see that a rise is a few metres ahead and the path is smooth. Or you crest a washout and face a steep immediate descent of a metre or two. In such cases, whilst you can see and adjust to what's ahead, the reactive HDC can't and wants to pull you up. The system is very heavy on discs and pads and, as 101RRS says, you just don't need it: low range with a locked torque converter and diesel engine braking ('though I admit I'm not sure if this is actually a factor anymore with modern engine management) does a perfect job on the steepest of declines. You can set the speed at which HDC operates and you can do it on the fly but I've never bothered playing with it I must admit.

FYI, I find that on most inclines, third low is my preferred gear, allowing me to shift up and down as appropriate.

I agree with the low range doing a good job, without needing HDC. But I have 32 inch tires, and find that now low 1st is a little bit too quick in some circumstances.

Fun fact... The fella in the video who rolled was wearing a AULRO T-shirt

Originally Posted by Spence

Fun fact... The fella in the video who rolled was wearing a AULRO T-shirt

Here is the original thread on the incident, where the driver comments on what happened D4 Rollover

Originally Posted by Spence

Fun fact... The fella in the video who rolled was wearing a AULRO T-shirt

Fun Fact....that’s cos the fella is on AULRO. Re reading my comments...yep, that’s what happened.

Originally Posted by DieselLSE

DSC: There's been a few occasions where the engine seemed to "die" for no apparent reason..................

HDC:.............................You can set the speed at which HDC operates and you can do it on the fly but I've never bothered playing with it I must admit.

FYI, I find that on most inclines, third low is my preferred gear, allowing me to shift up and down as appropriate.

I've only stalled the D3 once, I was out exploring tracks and came to a gate on a bit of an incline, so I decided to let it roll back a few metres to a place where I could turn around, but I forgot it was still in 1st, so it stalled.

The crucial part about HDC on the fly I want to know is, will it come on if you press the button after it has stalled, in case things go wrong?

Re: driving in low range, if you think it is going downhill too fast, let it roll a bit until the torque convertor locks up, that really retards it, or at least that is what I think happens from my experience.