4WD Low Settings Questions

[AceRider]

Reading the manual last night and have questions on Low settings:

- Forget asking about what I read about engaging Low on the fly; seems like I would permanently destroy the gears even though it sounded straight forward; put in neutral, no gas, engage Low.

- When in low, do you HAVE to choose gearing? I know you have the ability to choose 1/2/3 for take off, but after that, does it become an automatic or do you have to choose what gear you are in at all times in Low mode?

- Forgive my ignorance, but Low mode is totally different gearing from normal driving, right? Gear 1 bears not semblance to the twitchy first gear takeoff I experience in D, right?

 

[RoverGuy7]

You can select low and toss it in drive and be fine. The difference as far as selecting gears when in low vs high is that you hold the selected gear, it will only down shift from 3rd to 1st to keep from stalling in low, as opposed to high where it will kind of do what it wants. 1st in low and D in low are the same when starting off, but 1st will not shift into 2nd like it will in D (eventually it will if you get up to the rev limiter).

Shifting on the fly is fine, it's better practice to do it at a lower speed, say under 10, but it will work, and synchronize itself without causing damage up to it's cut off speed for shifting, 30 mph high to low I believe.

 

[AceRider]

Thanks. But if 1st is the same in H/L, what's does Low accomplish?

 

[RoverGuy7]

1st is 1st. It's the same gear ratio through the trans regardless, same with each other gear. Low range is in the transfer case. All the transmission gears stay the same, but the transfer case(what makes it 4 wheel drive) gears it way down when in low.
So if 1st gear is 4.171 : 1, in high range (which is direct drive through the t-case) your engine turns 4.171 times for every driveshaft rotation. In low range (geared down 2.93:1) your engine would turn 12.22 times for every driveshaft rotation, there by multiplying torque a good deal, but also limiting wheel speed per trans gear very much. The transmission gears are the same, and the transmission output speed per gear and engine speed is the same going into the transfer case, low range affects what comes out of the transfer case.
(the gear ratios are based off an LR3, don't have LR4 ratios handy)

 

[AceRider]

OK, so physical gears at the same, but the gearing is different. Got it.

I should stick to motorcycles, much simpler.

 

[Finlayforprez]

This is a great question and one that brings up a rather "dumb" question on my part.

When you guys are off roading, do you typically keep your LR4 in low gear? When I go off roading it is never really above 15 mph on certain dirt roads, then obstacle courses, forest terrain, etc. I tend to stay in high on the dirt roads, but then sometimes have to switch to low (go to neutral, switch to low) for changing terrains. I know the LR4 is different from my old 4x4 pick up that you don't really want to drive around in low range unless it's that type of terrain.

I guess I just don't know if it's OK to stay in low range, even on dirt roads going slow.

Thanks!

-David

 

[Kaaae]

i kept mine in low as most of the driving was below 20 and in some areas in sugar sand or mild articulation.

 

[Finlayforprez]

i kept mine in low as most of the driving was below 20 and in some areas in sugar sand or mild articulation.

That's how it is mostly for me as well where I go off roading, though it tends to also have some dirt roads with gravel, etc. I guess that is my biggest worry, whether or not the terrain warrants low, but then it might switch quickly.

I guess as long as I keep it below 20mph, even without much articulation, low should be fine.

 

[umbertob]

Unless they get really treacherous or very steep and slippery, I don't engage low range on dirt roads.

 

[AceRider]

So if 1st gear is 4.171 : 1, in high range (which is direct drive through the t-case) your engine turns 4.171 times for every driveshaft rotation. In low range (geared down 2.93:1) your engine would turn 12.22 times for every driveshaft rotation

So I would also assume that in Low you are burning at least 3x more fuel since engine speed is higher but forward progress is not?