Would Hill Descent Control work for what you need or would it be too slow for where you'll be driving?

 

No, HDC definitely wouldn't work as that's for low speed use only. I'm talking about driving on roads like the Bear Tooth Highway where you might encounter an extended section of 6% (or higher) grades, but with a speed limit of 50 mph, for example. In cases such as those, if you just leave the transmission in D and your foot off the gas and brake pedals you'll end up WELL past the speed limit and very likely over the edge of a steep cliff with a thousand foot drop and in a ton of trouble . If you ride the brakes the whole way down, it's not good for them, so engine braking is usually preferred with the brake pedal used to assist engine braking as needed.

I'm inclined to think that ASL might be perfect for this, but would like to have a better understanding of exactly how it works before I get into a situation where I need it.

 

Ah, that's what I figured.

It seems like using Sport mode to activate permanent manual might be closest it to what you want. But it's just going to keep the gear you put it in and not use the selected gear as your top limit. And from reading the manual, it will still intervene:

If continued use of manual mode is required, select Sport (S), to activate permanent manual mode. Permanent manual mode will be deactivated if the engine is over-revved or laboured, to prevent transmission and/or engine damage.

But as always, you have to experiment in real life before completely trusting the manual which isn't always proofread. As shown below:

While the transmission is set to permanent manual mode (i.e., using the paddles to change gear while in Sport (S) mode) and Dynamic mode is selected, transmission up-shifts are fully controlled by the driver. This means that
the transmission will not change up a gear automatically, even if the engine rev limit is reached.

As far as I know Dynamic mode is a Range Rover Sport feature. I think you're going to have to experiment and let us know what you find.

 

Ah, that's what I figured.

It seems like using Sport mode to activate permanent manual might be closest it to what you want. But it's just going to keep the gear you put it in and not use the selected gear as your top limit. And from reading the manual, it will still intervene:

Yes, I read that part about intervening which isn't a problem as I certainly wouldn't want to damage the transmission.

But as always, you have to experiment in real life before completely trusting the manual which isn't always proofread. As shown below:

As far as I know Dynamic mode is a Range Rover Sport feature. I think you're going to have to experiment and let us know what you find.

Well, I'm hoping that we have a few members here who have taken L405's on steep grades and have some real world experience to share. I'll be going on the trip with my brother and my dad, both of whom will be taking turns driving and if we end up on a steep grade, I'd really like to be able to tell them what to do rather than telling them to experiment and hope for the best . Here in eastern Massachusetts, there really isn't much opportunity to experiment with this sort of thing.

I can always try asking the dealer, but am not confident I'd get the best answer there. I'll also try posting something on the Expedition Portal forum and see what people there have to say.

 

i guess it depends on the speed that you want to tackle the descent. the paddle shifter is actually good for rev matching the decent for those brisk downshifting when traveling at 70-75mph descent from 80-85mph.

 

Although I haven't yet encountered this situation in my Rover, I have often used this type of feature in several other cars. I basically keep bumping down the gear until it reaches the desired speed. If I end up going too slow, I will bump it up a gear to allow for a bit more speed.

 

I asked pretty much the same question over on the Expedition Portal Land Rover forum and got the following answer from Scott Brady:

"Shift into sport, but do not activate a paddle shifter. The car will downshift nicely when you depress the brake pedal, and hold a lower gear. All of the modern Rovers will downshift aggressively in sport mode and provide assistive compression braking."

I wasn't aware of this feature of Sport mode, and it isn't explained at all in the owner's handbook (or I missed it), but this sounds like a pretty good option. And after giving it some more thought, being in full manual shift mode probably isn't much of a pain in this sort of situation as the goal is to prevent up shifts. Down shifts are really only needed if you want to have the engine braking help you go slower, so those would be done manually anyway. When you exit the steep grade, just shift back to D.

 

I am going to experiment with that.