Member Since: 02 Dec 2005
Location: Bradford, West Yorkshire
Posts: 6100
Controlling Steep Descent with an Auto Box
Argument brewing on another forum about whether or not it is a good idea to use reverse in an auto to control very steep descents and thus using the torque converter as the brake
Not necessarily a D3 question but more of a general one. Personally it seems crazy as...
a) There will be a massive strain placed on the TC
b) If you completely lose traction and need to accelerate you can't as you are in reverse!
Thoughts??2020 BMW X1 18d XDrive X-Line Auto
10th Nov 2010 2:10 pm
PaulP
Member Since: 04 May 2007
Location: Barcelona
Posts: 4317
I guess it may possibly work, but wouldn't ever want to try it.
I wonder if it would actually just stall the engine?
What's wrong with just low 1st? Or are we talking about 4x4s without a transfer and therefore no really short ranges?
Or with actually using the above with gentle braking using the foot brake?2006 Discovery 3 TDV6 SE AutoBuckingham Blue 2007 Golf GT DSG
10th Nov 2010 2:19 pm
Phat Face
Member Since: 08 Jul 2009
Location: Gloucester
Posts: 354
Completely agree with you, what a ridiculous concept. Low gear, low ratio, HDC is as much or more than you'll ever need. I'd of thought that using reverse gear whilst going steeply downhill forwards is a fastrack way towards a new gearbox.Lloyd "Phat Face"
2006 TDV6 HSE in Bonatti Grey
Club 19" GGAT's
Club B.A.S. EGR Bypass
10th Nov 2010 2:20 pm
1784
Member Since: 04 Sep 2009
Location: Almunge
Posts: 170
I agree, it seems like a really bad idea to intentionally attempt a steep decent going forwards but in reverse.
As you say, if things go out of hand and vehicle starts to slide, maybe going sideways and your instincts make you accelerate things will definitely not improve...
Better to limit speed by locking transmission in lowest forward gear and if that is not enough, a light foot on the brakes.
10th Nov 2010 2:24 pm
CFB
Member Since: 02 Dec 2005
Location: Bradford, West Yorkshire
Posts: 6100
The question arose due to a debate about the merits of manual v auto for off road, the consensus being that Auto was superior in most situations other than for engine braking on very steep descents, forget HDC that was not part of the discussion.2020 BMW X1 18d XDrive X-Line Auto
10th Nov 2010 2:33 pm
Gareth Site Moderator
Member Since: 07 Dec 2004
Location: Bramhall
Posts: 26774
Absolutely ridiculous suggestion
Everything I have ever been taught, or learned by experience, and all the electronics in HDC and ABS are about keeping the wheels turning in the direction of travel, so that the driver has as much directional control as possible. Even if the wheel speed is not relative to ground speed - ie you are sliding down, you will at least have an amount of directional control to keep the vehicle pointing down hill.
10th Nov 2010 2:39 pm
CFB
Member Since: 02 Dec 2005
Location: Bradford, West Yorkshire
Posts: 6100
I don't think they were suggesting spinning the wheels in reverse, just that by being in reverse gear and applying gentle throttle you are using the torque converter as a brake as it tries to halt the forward rotation.
I think it is is barmy but just wondered if this was an old and seldom used technique that I had somehow missed during my various instructor training courses 2020 BMW X1 18d XDrive X-Line Auto
10th Nov 2010 2:46 pm
Gareth Site Moderator
Member Since: 07 Dec 2004
Location: Bramhall
Posts: 26774
No Andy, I think its very misguided. If all they are talking about is reducing the speed of the wheels, why not use the brakes? you would have much more control!
10th Nov 2010 2:54 pm
DSL Keeper of the wheelie bin
Member Since: 11 May 2006
Location: Off again! :-)
Posts: 73079
In my non technical mode, daft idea!! With you going down hill and wheels trying to take you up hill backwards you're gonna loose control and just slide down. Or break your autobox. Or both!
10th Nov 2010 3:07 pm
Gareth Site Moderator
Member Since: 07 Dec 2004
Location: Bramhall
Posts: 26774
.....before Disco's with Traction control ABS & hill descent...with manual gearbox
the method was engaging a low gear in low ratio & driving on the throttle.....so as not to stall the engine
with an auto box same thing low ration command shift but you dont have to worry about stalling
.....& there is also Hill descent that does all of this & better that a person could do it (except in extreme conditions)
....so why even think about using reverse...weirdBREXIT - done properly.
Right now ...We need Government - not Politics
Save the Dipstick Flagbearer-keep it simple, less likely to fail campaign-agenda items:Starting Handles, Acetylene Lamps.
Founder: Dipsticks-R-Us Inc
D3 HSE-perfectly formed, passenger friendly...has real DIPSTICK
Jag XK-but sadly no DIPSTICK...HUGE design fault
FL2 has DIPSTICK..."real comfort in rear seats"
VW Golf wondermobile (?)..has real DIPSTICK
Morris Minor..original DIPSTICK technology..and a real KEY.
10th Nov 2010 3:10 pm
DSL Keeper of the wheelie bin
Member Since: 11 May 2006
Location: Off again! :-)
Posts: 73079
Gareth wrote:
... or turn sideways and overturn.
I was in the optimistic mode that my therapist encourages!!
10th Nov 2010 3:13 pm
Hanechdene
Member Since: 23 Jun 2009
Location: High Wycombe
Posts: 570
this was a theory banded about some years ago when people started trialing with autos.
No one successfully achieved anything by attempting this!
All they need to do is learn how to cadence break when driving with an auto and not be so heavy footed with the break peddle!
10th Nov 2010 5:34 pm
DSL Keeper of the wheelie bin
Member Since: 11 May 2006
Location: Off again! :-)
Posts: 73079
Of course yup don't have to just let HDC do it's thing (do all D3s have HDC??). If on a very steep descent where 1st low HDC feels too fast or you want to stop to admire the view, you can moderate it with a light touch on the brakes. IMHO both feet off the pedals on fear of death is a thing of the past.
...All they need to do is learn how to cadence brake !
I fully understand what cadence braking was (& it isnt relavent or required with any form of ABS) & agree when towing did make the difference of successfully stopping & not being "pushed" by the trailer....I've been there with heavy horse boxes & an overlight car !
But, I wouldnt have thought that cadence braking method would have been relavent on 4WD steep descents...here the whole ethic is to maintain traction & control of vehicle...if the wheels lock & you slide eventually you cant steer...Landrover teach that you do things ever so gently - hence the low ratio / box low gear method...also the way the army teach drivers for 4WD vehiclesBREXIT - done properly.
Right now ...We need Government - not Politics
Save the Dipstick Flagbearer-keep it simple, less likely to fail campaign-agenda items:Starting Handles, Acetylene Lamps.
Founder: Dipsticks-R-Us Inc
D3 HSE-perfectly formed, passenger friendly...has real DIPSTICK
Jag XK-but sadly no DIPSTICK...HUGE design fault
FL2 has DIPSTICK..."real comfort in rear seats"
VW Golf wondermobile (?)..has real DIPSTICK
Morris Minor..original DIPSTICK technology..and a real KEY.
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
