prolonged use of hill descent control

[paddy119]

Hi, Just a quick question regarding the prolonged used of HDC, i will be towing a off-road camper trailer that will be fully loaded up (it does not have brakes), we will be going to a camp site called west Kunderang in the wild oxley rivers NP, near Armidale, i am told that to get down to the valley there is a fairly steep long sections of downhill to negotiate,

My question is do i continue to use HDC and low range auto, or should i disengage HDC and engage 1st gear low range and use the brakes in short sharp bursts to stop over heating?

I there a chance of HDC over heating brakes?

Thanks Pat

[WhiteD3]

I'd be doing both. That way HDC will only kick in when required.

[Pedro_The_Swift]

disregarding the HDC for a sec,,
The D2 has an issue with lack of revs and the Torque Converter,,
no revs = no lockup = runaway car!
all can be averted by actually driving the car downhill, but not sure just how tricky the new command shift box is,,,

anyone?

[Redback]

Why do you have an offroad camper with no brakes:confused: fully loaded it will be over 750kg, that is the problem, not the HDC.

Give the car a rest every now and then, might take a bit longer to get to camp, but it might save some arse pucker moments as well, if the track is as steep and long as people would say, on most trips we have done, the steepness of tracks comes down to the experience of the person doing them, what one person calls steep another might think it's not.

You will work it out once your there, I would imagine.

Have fun, Baz.

[disco2hse]

disregarding the HDC for a sec,,
The D2 has an issue with lack of revs and the Torque Converter,,
no revs = no lockup = runaway car!
all can be averted by actually driving the car downhill, but not sure just how tricky the new command shift box is,,,

anyone?

Sorry. I know it's off topic.

I have experienced what you describe and certainly it gives the heebeegeebees :eek:

Keeping it in low 1st will at least ensure that revs are maintained at a higher level. But then you need to keep an eye on the temperature if it is for a long time.

[Redback]

disregarding the HDC for a sec,,
The D2 has an issue with lack of revs and the Torque Converter,,
no revs = no lockup = runaway car!
all can be averted by actually driving the car downhill, but not sure just how tricky the new command shift box is,,,

anyone?


Sorry. I know it's off topic.

I have experienced what you describe and certainly it gives the heebeegeebees :eek:

Keeping it in low 1st will at least ensure that revs are maintained at a higher level. But then you need to keep an eye on the temperature if it is for a long time.

I'm pretty sure the D3/D4 doesn't do this, the D3/4 has an adjustable HDC, to as low as 3kph.

Also you can't compare the D3/4 with the D2, they are vastly different vehicles.

Baz.

[disco2hse]

I'm pretty sure the D3/D4 doesn't do this, the D3/4 has an adjustable HDC, to as low as 3kph.

Also you can't compare the D3/4 with the D2, they are vastly different vehicles.

Baz.

Fair call. I don't think Pedro's intention was to compare the vehicles, it certainly wasn't mine. That's why I apologized for the off topic post.

[Mully]

The HDC is one of those things that's hard to trust but does work very well. I'd be trusting it for sure but the weight of the trailer pushing you down will be concerning if it has no brakes but I presume it does have at least hydraulic brakes like most good off road campers because that should definitely assist you as long as the incline doesn't create excessive drag.

Personally I'd go for HDC while watching temps and monitoring for undesired 'noises & smells' with the window down while watching for pullover spots after the first hundred meters or so.

Sounds like a great trip.

[ozscott]

Mate - I dont have this vehicle, but principles are the same. Always the lowest gear - so low range first where its steep. Then bring about assistance of HDC - ie use both.

Cheers

[101RRS]

In the D3 the HDC is fully adjustable but is not very smooth and gets uncomfortable - as soon as you do something else in the car like speed up, change range etc the HDC goes back to its highest speed setting so you have to bring the hdc speed back down.

I have found command shift (1st/2nd), low range far superior to HDC. I am not sure whether the TC locks up in these circumstances but if the correct gear is selected you have full engine braking and rarely need to use the brakes (remembering HDC is a brake based system).

So I would be using the gears in command shift and if for some reason that is not good enough then use HDC but it is a bit rough.

Garry

[Beckford]

I would be getting trailer brakes fitted to your off road trailer & a brake controller on your 4wd, if it is "fully loaded". Have you had it weighed on a weigh bridge" (you may get a shock). The RTA rules are as follows;

"BRAKING SYSTEM
The minimum braking system for a trailer depends on the type of trailer, its weight and the weight of the vehicle:
0 – 750 kg loaded weight – no brakes required.
751 – 2000 kg loaded weight – braking on both wheels on at least one axle.
2001– 4500 kg loaded weight – braking on all wheels, and an automatic breakaway system in case the trailer becomes detached from the vehicle. Brakes must be operable from the driver’s seating position."

[OffTrack]

disregarding the HDC for a sec,,
The D2 has an issue with lack of revs and the Torque Converter,,
no revs = no lockup = runaway car!
all can be averted by actually driving the car downhill,

Just started a thread in the D2 forum regarding this puddle of "Bad Oil".... :wasntme:

http://www.aulro.com/afvb/discovery-2/135054-descending-hills-d2-auto-lockup-braking.html

[Tote]

My experience off road (without a trailer ) mirrors garrycol's. I use an appropriate gear 1st or second low range and have never had a runaway. In the event that the incorrect gear is selected pressing the yellow button quickly brings the vehicle safely to a condition where you can easily change to a lower ratio.
I would imagine that the torque converter is locked by the computer on downhill runs anyway so a runaway is not possible due to a lack of engine braking.

Regards,
Tote

[DiscoWeb]

Hi, Just a quick question regarding the prolonged used of HDC, i will be towing a off-road camper trailer that will be fully loaded up (it does not have brakes), we will be going to a camp site called west Kunderang in the wild oxley rivers NP, near Armidale, i am told that to get down to the valley there is a fairly steep long sections of downhill to negotiate,

My question is do i continue to use HDC and low range auto, or should i disengage HDC and engage 1st gear low range and use the brakes in short sharp bursts to stop over heating?

I there a chance of HDC over heating brakes?

Thanks Pat

Pat,

Whilst not with a camper trailer I used HDC to descend from Mt Pinnibar in the Vic High Country once due to a transmission fault that mean I had a concern with relying on 1st low range.

The decent was very steep and very long and I had no problem with over heating but did stop on the flatter sections for short periods as a precaution. In saying that I did not once get that burning brake smell or any sense of the vehicle not handling the prolonged decent with HDC.

I would guess (and it is a guess) that as long as you take it easy, are aware and cautious the HDC combined with 1st low would handle most steep descents.

I have not idea about trailer brakes so will leave that to other to discuss.

Enjoy the trip, I hope you can put a report up in the trip reports section once complete.

George.

[Pedro_The_Swift]

no, not comparing, maybe just a bit of a hint is all,, but if what garry says about the resetting of the speed everytime,, it doesnt look like LR fixed the problem.

As all have said,, put brakes on it next time;)

[paddy119]

Thanks for all the advice, i have used HDC for short downhills and have been impressed with its control, i think i will use a combined approach of low gearing and HDC and inspect brakes periodically, i will let you guys know how the trip goes, only 2 weeks to go, West Kunderang, Byron Bay, Noosa, then off to Fraser Island for a week. Cheers

[Blknight.aus]

dont worry so much about the brakes themselves...

worry more about the ABS module.

IF youve been working the TC HDC and ABS hard it has the potential to overheat and shut down. It doesnt mean the brakes are gone but it does mean you have to drive old school without the electronics untill the pump cools down and restarts.

[amaruskanic]

Does anyone know if HDC applies the brakes evenly across all 4 wheels?
From previous experience when I used HDC for a long descent in a D2 after the transmission went into limp home mode was that it doesnt.
When I reached the bottom smoke was pouring off the right rear wheel, whilst the others seemed ok. In hindsight I would have been better off manually applying the brakes.

[vnx205]

Does anyone know if HDC applies the brakes evenly across all 4 wheels?
From previous experience when I used HDC for a long descent in a D2 after the transmission went into limp home mode was that it doesnt.
When I reached the bottom smoke was pouring off the right rear wheel, whilst the others seemed ok. In hindsight I would have been better off manually applying the brakes.

At a rough guess, i would expect that it would not apply the brakes to any wheel that had no traction, such as one that was not touching the ground.

[gghaggis]

Does anyone know if HDC applies the brakes evenly across all 4 wheels?
From previous experience when I used HDC for a long descent in a D2 after the transmission went into limp home mode was that it doesnt.
When I reached the bottom smoke was pouring off the right rear wheel, whilst the others seemed ok. In hindsight I would have been better off manually applying the brakes.

Discussed in this thread:

http://www.aulro.com/afvb/d3-d4-rrs/103730-hill-decent-slippery-stuff-4.html

Different algorithms and control modules in a D3/4 compared to a D2.

Cheers,

Gordon

[camel_landy]

The thing to remember with HDC is that it is a seconary system for speed control. The primary system is always your engine brakeing through selecting the lowest practical gear... Even in the Freelander!

In other words, always have HDC on, select 1st Lo for your descents and keep off the foot brake!!! ;)

M