4Lo Question

[CLHickman]

4Lo is the same as 4Hi, just with lower gearing.

It in itself will not save you from a sticky situation. Think of it like this:

4Lo has all of the power going through the drive train. So, if you have a wheel that comes free, the law of least resistance will have all of the power go to that wheel.

Our rigs have a CDL, which is not bad, but not a "locker." In this situation, if you have the CDL locked, then 50% of the power goes to the rear and 50% goes to the front. This means that if that same wheel breaks free, only the power in that differential will go to that wheel. The other 50% will still work pushing the truck. If you get a front and rear wheel spinning, you're stuck.

Lockers add more to this equation by ensuring that differential it is installed on will split the power to each wheel. That is why there is a lot of conversation about putting front and rear lockers on these trucks. If you do that, then you are putting 25% power to each wheel. This means that you could have 3 wheels spinning and still have a wheel working to move the truck.

DISCLAIMER: Our trucks have a system called ATRAC that kind of acts like lockers.

If I've flubbed this up, please help!

 

[Swampmonger]

@CLHickman I appreciate the answer. I guess what I'm confused about is if using 4L is an off-nominal configuration like using a front or rear locker? I put my truck in 4L when needed and I crawl at idle until I'm over the obstacle and then I put it back in 4H. I don't use the gas pedal at all. My question comes from the fact that it sounds like I should just keep it in 4L driving between obstacles where the trail is still pretty hairy.

 

[CLHickman]

@CLHickman I appreciate the answer. I guess what I'm confused about is if using 4L is an off-nominal configuration like using a front or rear locker? I put my truck in 4L when needed and I crawl at idle until I'm over the obstacle and then I put it back in 4H. I don't use the gas pedal at all. My question comes from the fact that it sounds like I should just keep it in 4L driving between obstacles where the trail is still pretty hairy.

This is pretty much how I've used 4Lo on the trail. Many times there are large stretches between obstacles, so I'll cruise a long in 4Hi until I get to it. Most will probably say that they are in 4Hi most of the time on trails, as we have been.

The real champ, as I see it, for our rigs is the ATRAC/CRAWL system. I've not had a problem with it at all, unless I've done something truly stupid. Like resting the frame on compact snow and building a nice trench under each wheel

 

[Dan Higgins]

So I learned 4W driving from Land Rover's professional trainers. Nothing against the Land Cruisers but a certain segment of the Land Rover community took/take "expedition offroading" or overlanding in touch situations very seriously. (Check out the videos online of the Camel Trophy competitions.) One of those trainers I learned from is a guy named Bill Burke who is very well regarded and a Camel Trophy competitors (or maybe winner.) Also received training during the Overland Expo events. In every case I was taught to use 4L any time you are driving off road as it gives you more control and you don't need the 4H gearing because you aren't going that fast when going offroad. The Land Rover LR4 had a similar transmission setup to the LC. (Not talking about lockers here. Just the use of 4H/4L.)

A major difference I see between the LR4 and the LC is that to enable the use of multi-terrain traction control settings, multi-terrain camera views, etc you need to be in 4L. For me that is another reason to simply change to 4L whenever I am offroad. Now, driving 50 mph down a straight, well-graded dirt or gravel road is not "offroad" for me. Off-pavement is not the same as off-road.

Related uses of 4L. Descending anything steep and "slick" or loose where you will benefit from having engine compression applied to all 4 wheels to help manage your speed without needing to use and possibly overheat the brakes.

There are a lot of great videos on driving Land Rover's offroad. Highly recommended. Most or nearly all of the principles and even the techniques will apply to the LC.

Bottom line is that I almost always drive in 4L/S3 or 4L/S2 when offroad. Speed is about right for what/how I drive. S3 (and sometimes S2) is good for climbing steeps (keeping up momentum and all). Also will move up to S4 and S5 on occasion. Why? Because it is easier to just stay in 4L and shift up/down to manage speed, RPM, torque, engine compression, etc. Not need to stop, shift to neutral, etc. Multi-terrain modes can be switched easily.

 

[Sandroad]

Here are some helpful links from the FAQs:

FAQ Discussion: Crawl, Multi-Terrain, Optional Lockers or ATRAC when best to use each





How Differentials Work

 

[CLHickman]

@Dan Higgins - How fast are you going in 4/5th gear in 4Lo? You've got the 8-speed transmission, correct?

 

[linuxgod]

Sorry to piggyback on the OP's question, but since the thread has gone a little more general I'd like to get some clarification. I look at 4L like lockers. I only use it if I get in trouble (or think I might). Am I looking at it wrong? It sounds like if I'm on a trail where I have to ride the brakes and be careful on the gas that maybe I should be in 4L?

Short answer is you can use 4L much more often than lockers. With lockers, you really only want to engage them when you're either stuck, or in a situation where you think you might get stuck if you don't enable them. (The only factory locker on the US LC is the center diff, which locks front-rear at 50/50, btw). But you can cruise trails in 4L all day long if you'd like, just realize your gas mileage and top speed will suffer.

FWIW once I'm on a trail I tend to stay in 4L up to ~20-25 mph, just running in S3 or maybe S4. I'll downshift if the trail gets hairier. If I can go faster I'll shift into 4H, but I prefer to stay in 4L most of the time since the transition to/from 4L/4H/4L requires you to stop. As others have said, 4L is just a taller gearing, you can even use it on dry pavement if you are on a really steep hill with a load (for instance).

 

[Swampmonger]

Thanks everyone for the help. We're headed into the mountains for NYE. Can't wait to try it in 4L.

Follow up question...

If the trail is rough enough to keep me under 10mph, but traction isn't really an issue should I go into 4L with CDL *unlocked* to make my truck steer a little easier and make it more "drivable"?

 

[TonyP]

I almost never use the CDL, L4 has been sufficient so far. That being said, 75% of the time I'm in H4 on a trail and I'll attempt whatever the obstacle is in H4 then use L4 as needed. If you can't make an obstacle in H4, you'll always have L4 as an option. If you're always in L4, you have no other options besides recovery gear. Different strokes for different folks. Plus, slowly chugging along in L4 on a dirt road is kinda boring, briskly driving in H4 is more enjoyable.

 

[Dan Higgins]

Others can comment more on CDL as I rarely use it. @linuxgod addresses CDL. But you can absolutely run 4L all day long (as I do and as others have pointed out. What suffers is MPG. Since @linuxgod and I both pull good size trailers, we probably use it to climb out of a steep road or driveway towing a trailer.

Running in 4L has a somewhat different feel and you will definitely hear the tranny whining. Part of that is because we have become accustomed to hearing engines running at lower (1500-2000) rpm all the time to keep MPG down and we barely notice it. You will hear the tranny in 4L just as you will when driving at mid-3000 RPM (peak torque zone) when towing a trailer up a hill.

@CLHickman, you asked how fast I am going in 4L/S4-5. I don't pay a lot of attention to the speedometer because my eyes are usually glued to the road. But I seem to remember it being about 40-45 mph. For more clarification, the reason I shift to S4 or S5 is because I am in S2 or S3 (I am most often in 4L/S3 when driving offroad as it just "feels" right for me) and I see/hear the RPM going higher than necessary. A quick push forward of the shift lever frees the transmission to shift up to S4 or S5 and i immediately see/hear the RPM drop. If I'm on the flats I'll let it drop to about 1500. If I am about to hit a steep or slow section I'll shift down. But the automatic shifting is pretty good about down shifting. The times I most often need to force this issue is going downhill when I want more engine braking control.

Of course a lot of this is experience and feel and will be different for the 6-speeds. @CLHickman, yes, I have the 8-speed. So the lower gears on my primary "cluster" (sorry, I tend to use cycling terminology) are lower than on the 6-speed trannies.

@Swampmonger, I very highly recommend to you and actually everyone to spend a couple hours driving around trails and back roads in 4L and getting a feel for it. "Feel" and sound are very important when driving offroad as you can't always be looking down at your instrument cluster. Use 4L in Drive and listen/feel for when it shifts. Then move it to S-mode and play with it. Get used to the fact that in S-mode you are setting the upper limit for the gear, not the actual gear. Shifting to S3 will allow the transmission to automatically shift between 1, 2 and 3. This actually works out great. I never find that I am trying to force the tranny into a higher gear - the bias towards lower MPG tend to make that happen automatically. Rather, I find I want to set the upper limit (which is what happens) so as to keep the RPM high enough for good engine braking. BTW, I drive in S-mode a LOT - even when not in 4L. I leave D for general around town and freeway driving.

 

[Dan Higgins]

I almost never use the CDL, L4 has been sufficient so far. That being said, 75% of the time I'm in H4 on a trail and I'll attempt whatever the obstacle is in H4 then use L4 as needed. If you can't make an obstacle in H4, you'll always have L4 as an option. If you're always in L4, you have no other options besides recovery gear. Different strokes for different folks. Plus, slowly chugging along in L4 on a dirt road is kinda boring, briskly driving in H4 is more enjoyable.

See? Tony is young, skilled, no kids, unmarried. So he can tear down the trails. OTOH, I am old, slow and cautious and often have my wife with me.

Actually, having learned on a Land Rover LR4 and from their trainers, there was one issue with the vehicle. At about 25-30 MPH the adjustable height air suspension if in "off road height" sends you a warning and then eventually drops down to "normal" height. So if you're driving down a smooth, flat track with a high center due to "ruts" then you can't go over about 25 MPH. I love the fact that I get about the same clearance or more with the lift on my LC and I can go as fast as I want (which will most certainly be slower than Tony.)

And as for speed on rough roads, I was told by a resident of Escalante, UT that the best speed for washboarded roads is 40 MPH. (Hole In The Rock road being the subject of our conversation.) So I tried it. Sheez. Maybe if I was a rally driver! But of course, the person who gave us that guidance (great guy BTW - Mack, the chef at the Slot Canyons Inn) had broken most of the bones in his body in crashes and rollovers driving back roads (sometimes while under the influence).

 

[TonyP]

See? Tony is young, skilled, no kids, unmarried. So he can tear down the trails. OTOH, I am old, slow and cautious and often have my wife with me.

Actually, having learned on a Land Rover LR4 and from their trainers, there was one issue with the vehicle. At about 25-30 MPH the adjustable height air suspension if in "off road height" sends you a warning and then eventually drops down to "normal" height. So if you're driving down a smooth, flat track with a high center due to "ruts" then you can't go over about 25 MPH. I love the fact that I get about the same clearance or more with the lift on my LC and I can go as fast as I want (which will most certainly be slower than Tony.)

And as for speed on rough roads, I was told by a resident of Escalante, UT that the best speed for washboarded roads is 40 MPH. (Hole In The Rock road being the subject of our conversation.) So I tried it. Sheez. Maybe if I was a rally driver! But of course, the person who gave us that guidance (great guy BTW - Mack, the chef at the Slot Canyons Inn) had broken most of the bones in his body in crashes and rollovers driving back roads (sometimes while under the influence).

Haha well there's a fine line between cautious and reckless. Granted, I'm still trying to find that line but I do enjoy dabbling in the latter.

As for speed on washboards. Every vehicle is different; tires, psi, weight, suspension, ect all play a role in what speed will cause the vehicle to "skip" over the rutts and be semi-smooth. The road into the serengeti was atrocious at 40mph in the Troopy but manageable at 50mph.

 

[Swampmonger]

I almost never use the CDL, L4 has been sufficient so far. That being said, 75% of the time I'm in H4 on a trail and I'll attempt whatever the obstacle is in H4 then use L4 as needed. If you can't make an obstacle in H4, you'll always have L4 as an option. If you're always in L4, you have no other options besides recovery gear. Different strokes for different folks. Plus, slowly chugging along in L4 on a dirt road is kinda boring, briskly driving in H4 is more enjoyable.

I think this is where the communications get muddy. I'm not talking about driving on dirt roads. Yes, they are roads. Yes, they are dirt. Yes, they do connect one small mountain town to another, but there is no option to drive briskly. If I drove briskly I'd be beating the crap out of my truck, cargo would be flying everywhere, we'd be banging our heads on the windows and headliner, I'd be stressed and irritable, and my girlfriend would be pissed. I'm not talking about Moab level of difficulty here, but I'm also not talking about dirt roads, either.

 

[Swampmonger]

Others can comment more on CDL as I rarely use it. @linuxgod addresses CDL. But you can absolutely run 4L all day long (as I do and as others have pointed out. What suffers is MPG. Since @linuxgod and I both pull good size trailers, we probably use it to climb out of a steep road or driveway towing a trailer.

Running in 4L has a somewhat different feel and you will definitely hear the tranny whining. Part of that is because we have become accustomed to hearing engines running at lower (1500-2000) rpm all the time to keep MPG down and we barely notice it. You will hear the tranny in 4L just as you will when driving at mid-3000 RPM (peak torque zone) when towing a trailer up a hill.

@CLHickman, you asked how fast I am going in 4L/S4-5. I don't pay a lot of attention to the speedometer because my eyes are usually glued to the road. But I seem to remember it being about 40-45 mph. For more clarification, the reason I shift to S4 or S5 is because I am in S2 or S3 (I am most often in 4L/S3 when driving offroad as it just "feels" right for me) and I see/hear the RPM going higher than necessary. A quick push forward of the shift lever frees the transmission to shift up to S4 or S5 and i immediately see/hear the RPM drop. If I'm on the flats I'll let it drop to about 1500. If I am about to hit a steep or slow section I'll shift down. But the automatic shifting is pretty good about down shifting. The times I most often need to force this issue is going downhill when I want more engine braking control.

Of course a lot of this is experience and feel and will be different for the 6-speeds. @CLHickman, yes, I have the 8-speed. So the lower gears on my primary "cluster" (sorry, I tend to use cycling terminology) are lower than on the 6-speed trannies.

@Swampmonger, I very highly recommend to you and actually everyone to spend a couple hours driving around trails and back roads in 4L and getting a feel for it. "Feel" and sound are very important when driving offroad as you can't always be looking down at your instrument cluster. Use 4L in Drive and listen/feel for when it shifts. Then move it to S-mode and play with it. Get used to the fact that in S-mode you are setting the upper limit for the gear, not the actual gear. Shifting to S3 will allow the transmission to automatically shift between 1, 2 and 3. This actually works out great. I never find that I am trying to force the tranny into a higher gear - the bias towards lower MPG tend to make that happen automatically. Rather, I find I want to set the upper limit (which is what happens) so as to keep the RPM high enough for good engine braking. BTW, I drive in S-mode a LOT - even when not in 4L. I leave D for general around town and freeway driving.

This is what I plan on doing this weekend. I'll drive to Crown King in 4H as usual then go out on the unmaintained roads and play around. Now that I know that driving in 4L won't grenade my drivetrain I'll go out and see how it goes. Something tells me I'm going to enjoy driving the rough parts much more in 4L instead of fighting them and riding the brakes in 4H.

 

[TonyP]

I think this is where the communications get muddy. I'm not talking about driving on dirt roads. Yes, they are roads. Yes, they are dirt. Yes, they do connect one small mountain town to another, but there is no option to drive briskly. If I drove briskly I'd be beating the crap out of my truck, cargo would be flying everywhere, we'd be banging our heads on the windows and headliner, I'd be stressed and irritable, and my girlfriend would be pissed. I'm not talking about Moab level of difficulty here, but I'm also not talking about dirt roads, either.

I was speaking in general terms, and my own view, not your case specifically. Whatever your comfortable with, that is the correct answer as to how quickly you should drive.

 

[Dan Higgins]

I was speaking in general terms, and my own view, not your case specifically. Whatever your comfortable with, that is the correct answer as to how quickly you should drive.

Yeah. I was obviously pulling Tony's chain a bit. He is experienced and knows what works for him. And I know he adapts his driving to the conditions.

My latter comment is the key and why this was a good thread - to help folks understand that 4L is a very viable option and can be used much more than one might think. But that doesn't mean that it is "best" to use it all the time. These vehicles have lots of ways to skin a cat so sometimes it is a matter of driving style and terrain. If I am on a section of flat-ish, smooth road between more challenging sections and that flat-ish section is a couple miles or more long I would likely shift back to 4H/S. If it is less than a mile then I'll leave it in 4L/S5 and let the auto tranny do its thing.

But that's me. What I like about 4L at "my" typical off road speeds is that when I back of the skinny pedal I feel the engine doing more to slow the vehicle. I like that. It just feels like I have a bit more control with the skinny pedal. It is noticeable when I am back in 4H because I'll back off the gas and not feel the same slowing (engine braking) of the vehicle and if I'm going down a steep-ish hill it is unsettling for just a moment. It just feels different. But that is very personal. These are the things you learn from playing with it.

Have fun!

 

[Dan Higgins]

I was speaking in general terms, and my own view, not your case specifically. Whatever your comfortable with, that is the correct answer as to how quickly you should drive.

Oh, and as for speed, since I learned on a Land Rover, their slogan is, "As slow as possible, as fast as necessary." Probably not everyone's cup of tea. And, yes, slow as possible can be dang boring. What does that even mean? 2 MPH on pavement? So clearly it is relative. Maybe Land Rover advocates this approach at their driving schools because they don't want some overexcited newbie smashing one of their Range Rovers into a tree. Or maybe their afraid that their vehicles will fall apart if you drive them too hard. But OTOH, there are times when it makes sense.

 

[Markuson]

@CLHickman I appreciate the answer. I guess what I'm confused about is if using 4L is an off-nominal configuration like using a front or rear locker? I put my truck in 4L when needed and I crawl at idle until I'm over the obstacle and then I put it back in 4H. I don't use the gas pedal at all. My question comes from the fact that it sounds like I should just keep it in 4L driving between obstacles where the trail is still pretty hairy.

One of the most important uses for 4Lo (besides the obvious...super steep climbs, rock-crawls, etc.) is low-speed **engine braking** on long, messy, curvy, steep, or repetitive descents...even if not super technical. Of course you can use 4Hi manual shifting to slow your descent too, but in the bumpy stuff where excessive bursts of down-hill speed can be dangerous, 4Lo engine braking is essential.

For example... If you really wanted to, you could (not advised) drive UP most of Ouray, Colorado's trails to 14,000 feet in 4Hi, because most of it is not terribly steep or technical. But..... you will **FRY your brakes** in VERY short order on the way DOWN if you aren't using engine braking in 4Lo...and where 4Hi could lead to too much speed. If you ride your brakes in either 4Hi or 4Lo, you can get yourself into serious brake-softness trouble if you super-heat your brakes without thinking about it. Then when you really need to stomp on them to stop...you keep moving. Not good.

You really can avoid braking almost entirely much of the time except for quick stops, or quick adjustments. Today in the desert, I barely touched my brakes while going up and down repetitive steep up/down. If you have larger tires, its even more important with more leverage/friction/heat on your brakes. Even stock size can superheat quickly in extended descents.

I've followed drivers who were riding the brakes til they were SMOKING & barely able to stop any more & it took a scary moment for him to see the need for engine braking.

 

[TeCKis300]

Others can comment more on CDL as I rarely use it. @linuxgod addresses CDL. But you can absolutely run 4L all day long (as I do and as others have pointed out. What suffers is MPG. Since @linuxgod and I both pull good size trailers, we probably use it to climb out of a steep road or driveway towing a trailer.

Running in 4L has a somewhat different feel and you will definitely hear the tranny whining. Part of that is because we have become accustomed to hearing engines running at lower (1500-2000) rpm all the time to keep MPG down and we barely notice it. You will hear the tranny in 4L just as you will when driving at mid-3000 RPM (peak torque zone) when towing a trailer up a hill.

@CLHickman, you asked how fast I am going in 4L/S4-5. I don't pay a lot of attention to the speedometer because my eyes are usually glued to the road. But I seem to remember it being about 40-45 mph. For more clarification, the reason I shift to S4 or S5 is because I am in S2 or S3 (I am most often in 4L/S3 when driving offroad as it just "feels" right for me) and I see/hear the RPM going higher than necessary. A quick push forward of the shift lever frees the transmission to shift up to S4 or S5 and i immediately see/hear the RPM drop. If I'm on the flats I'll let it drop to about 1500. If I am about to hit a steep or slow section I'll shift down. But the automatic shifting is pretty good about down shifting. The times I most often need to force this issue is going downhill when I want more engine braking control.

Of course a lot of this is experience and feel and will be different for the 6-speeds. @CLHickman, yes, I have the 8-speed. So the lower gears on my primary "cluster" (sorry, I tend to use cycling terminology) are lower than on the 6-speed trannies.

@Swampmonger, I very highly recommend to you and actually everyone to spend a couple hours driving around trails and back roads in 4L and getting a feel for it. "Feel" and sound are very important when driving offroad as you can't always be looking down at your instrument cluster. Use 4L in Drive and listen/feel for when it shifts. Then move it to S-mode and play with it. Get used to the fact that in S-mode you are setting the upper limit for the gear, not the actual gear. Shifting to S3 will allow the transmission to automatically shift between 1, 2 and 3. This actually works out great. I never find that I am trying to force the tranny into a higher gear - the bias towards lower MPG tend to make that happen automatically. Rather, I find I want to set the upper limit (which is what happens) so as to keep the RPM high enough for good engine braking. BTW, I drive in S-mode a LOT - even when not in 4L. I leave D for general around town and freeway driving.

This is really useful! I have to agree with the judicious use of 4L when off-road, even when not in particularly knarly stuff. From a mechanical standpoint, 4Lo benefits the drivetrain as it's not lugging around putting a lot of heat into the motor and transmission. The motor runs in a lower load range with the gearing advantage. It can circulate its fluids more readily to keep everything running cool. For the transmission, 4Lo keeps the torque converter cooler by working in an rpm range that allows it to not slip as much (and generate excessive heat). And all the driver control advantages already touched on. A win-win.

 

[linuxgod]

Others can comment more on CDL as I rarely use it. @linuxgod addresses CDL. But you can absolutely run 4L all day long (as I do and as others have pointed out. What suffers is MPG. Since @linuxgod and I both pull good size trailers, we probably use it to climb out of a steep road or driveway towing a trailer.

Running in 4L has a somewhat different feel and you will definitely hear the tranny whining. Part of that is because we have become accustomed to hearing engines running at lower (1500-2000) rpm all the time to keep MPG down and we barely notice it. You will hear the tranny in 4L just as you will when driving at mid-3000 RPM (peak torque zone) when towing a trailer up a hill.

I engage the CDL regularly just driving down my alley or when there's a bit of snow just to exercise the actuator. Otherwise I get the dreaded flashing CDL every so often. Sometime before the warranty is up I'll take it to the dealer and complain. Otherwise I really haven't felt the "need" for it except when on a really rocky or steep (and slippery) trail.

I haven't needed to use 4L with my trailer uphill, though I can imagine using it. The few times when I've felt 4H was insufficient I was climbing at >10,000', but the truck managed in 1st gear OK.

BTW for the benefit of others on the forum, the transmission whine in 4L is because the gears are straight cut instead of helical. It's just noisier due to the design.