What is the difference between 4X4 Low and CDL? (1 Viewer)

[Kamran Khan]

I want to educate myself about the difference between Central Differential Lock and 4X4 Low. My sweet heart has 4x4 low but it don't have button for Central Differential Lock. I have seen Clay's video on Youtube about installing CDL switch in his Cruiser.
Do I really need to have that button installed in my Cruiser to make it's CDL work or I can engage it by just putting my Cruiser in 4x4 Low.
Don't all the Cruisers come with factory installed lockers. If they don't how does locker look like and then what is 4x4 Low is for? And what is the 7 pin mod used for?

 

[Ken C]

Low just means that you are in low range "Crawl" mode.

There is 4x4 low (4L) and 4x4 high (4H). Both are CDL.

The CDL switch you are talking about is for 4x4 High (4H). High meaning "normal speeds" and not "crawl"

I think the main practical use for the CDL switch is to turn off ABS on dirt roads. I'm from socal so I might be wrong.

All cruisers come with center differential. Some come with front+rear (switch is on the left side of the steering wheel).

Try this vid:

 

[Kamran Khan]

So that means my cruiser don't have factory lockers because I don't have factory installed CDL switch. But if I buy CDL switch I guess is not going to help. I would still need lockers?

 

[Ken C]

That CDL switch is something else.

CDL switch is not the same as the factory locker switch.

They are 2 different things.

The CDL switch only gives you center differential in high range. 2 wheels moving at one time.

Factory lockers lock your front and rear axles. 4 wheels moving at one time.

 

[Kamran Khan]

I think you mean the round switch is for lockers and the rectangle is for Center Differential Lock. Am I right?

 

[120mm]

The following is an (over) simplistic explanation of my understanding of this subject. So, please, take it with that in mind.

I find CDL really useful for driving at road speed through deep snow or up steep, slippery slopes faster than "crawl" speed.

The 7 pin mod unlocks your center differential in low. For me, this allows me to navigate steep, serpentine roads while fully loaded without causing my LC to "toboggan" while doing switchback turns. If you've ever experienced 4WD tobogganing, you would remember it.

Having almost died a few times for the lack of these two capabilities, they are well worth the effort, imo.

I do not have locking differentials; most LC owners never really use them, as the AWD is quite capable for the majority of off road travel. If you need a locker, for all but the most extreme off-roaders, a single locking differential in the rear more than satisfies their needs. These are installed in the rear differential and go by various names like "Aussie Locker" "Lokka" or "lunch box locker" and are relatively easy and inexpensive to do.

Some people like/need the additional capability of a front locker as well. Some front lockers deactivate the AWD and convert it back to 4WD. Some play well with AWD.

It's important to understand what your "needs" actually are.

 

[Locked79]

Correct

 

[Nors]

Low just means that you are in low range "Crawl" mode.

There is 4x4 low (4L) and 4x4 high (4H). Both are CDL.

The CDL switch you are talking about is for 4x4 High (4H). High meaning "normal speeds" and not "crawl"

I think the main practical use for the CDL switch is to turn off ABS on dirt roads. I'm from socal so I might be wrong.

All cruisers come with center differential. Some come with front+rear (switch is on the left side of the steering wheel).

Try this vid:

This video is misleading to me considering all of our 80s are AWD
Am I correct?

 

[Alex Fogg]

I may be wrong, but Landtank described it to me this way: Our trucks are in all time 4WD, like AWD, until you loose traction completely on one wheel, if that wheel is spinning then all the power goes to that wheel, if you have the CDL and engage it then you split the power between the front and rear, and you would need to have a front and rear wheel spinning to loose traction, then you could shift to 4 Low and lock the rear or all four wheels (if you have lockers) to crawl out of just about anything. I think this is correct, but feel free to educate me if I'm wrong.

 

[Heckraiser]

The CDL switch allows you to lock the center differential (located in the transfer case) in high range. This changes the truck from essentially AWD (when power can go freely to front or rear depending on traction conditions) to 4WD (when power is split equally between the front and rear axle). Even if you do not have a switch, the center diff automatically locks when you shift into 4Lo. All landcruiser center diffs are "locking" whether they have a switch or not, it's just a question of whether you want to be able to lock and unlock manually in 4Hi.

I personally have never found a need for a CDL switch. Normal 4Hi operation has gotten me where I need to go in poor traction conditions.

7 pin mod allows the center diff to remain unlocked (AWD mode) in low range. I also have never found a need for this, but I can see how it would be useful in tight switchbacks where the truck has good traction (like Moab slickrock, for instance). To me, the need is minimal though... I just let the tires scrub like I have since the good ol' days.

Both of these are not to be confused with front and rear differential lockers. That is an entirely different topic, and these have a much bigger impact on your trucks off road capability.

 

[IanB]

Most 80's are full time AWD/4WD, meaning you have power going to any 1 tire at a time, if you lose traction at any one tire, you could be stuck with one tire spinning. CDL locks the center differential, sending 50/50 power to the front and rear axles, giving you power to at least 1 tire on each axle, this is what I call "4x4". You would need one tire on each axle spinning to get stuck in this configuration.

Some 80's have front & rear lockers as well, controlled by the rotary knob pictured above. Stock configuration you need the CDL engaged to use the F&R lockers, meaning if you don't have a CDL button, you need to be in low range to use your F&R lockers. The addition of a CDL switch allows you to use the lockers in high range as well, as you can lock the CDL in high range. The pin-7 mod disables the auto CDL lock when you shift to low range.

Turn the rotary knob to the 1st position, and it locks the rear diff, meaning you've got both rear tires driven, and one on the front axle. You'd need all 3 driven tires with no traction to get stuck. Turn the rotary knob to the 2nd position, and it locks your front diff, giving you 25% power to all 4 tires, tank mode.

High/low range is a simply different gear set, it really has nothing to do with 4x4 and how or where the power is being sent, but it gets tied into the conversation due to the CDL auto locking in low range on the trucks with no CDL button. The OEM configuration requires you to be in low range to use your CDL and F&R lockers, but low range on its own doesn't send power to more tires. I hope this makes sense.

 

[inkpot]

Having the CDL switch also allows me to turn off the transfer case locker (Center Differential Lock). This results in a small reduction in driveline stress, which also makes the rig handle a little looser. I like this because it easier to " hot rod" on easy trails with lots of tight turns but only easy to moderate challenges. Not a lot of difference, but I do enjoy being able to make really good time on sections of trail I have run dozens of times recently. It allows me to spend more time on the more challenging stuff at the far end. John

 

[Landseer]

If you don't have a CDL switch you can still lock the center diff in HI: set transfer case to low, wait until the CDL light come on then remove the diff fuse (located in the fuse block to the left of the steering wheel) then set transfer case back to HI. The center diff lock is electronically actuated so without power it will stay locked in HI.

 

[Pitch]

Another CDL benefit: with a rear auto locker, like an Aussie or Lock Rite, engaging the CDL button improves handling on snowy or icy roads. Mine was engaged all of last week with recent weather that we have had. However, on dry pavement, this results in the familiar 4wd bucking.

 

[Kamran Khan]

When I engage my cruiser's 4x4 low. It kind of jumps when its about to start running. when it starts running in 4x4 low the front differentials also make constant clicking noise. Is it normal?

 

[IanB]

When I engage my cruiser's 4x4 low. It kind of jumps when its about to start running. when it starts running in 4x4 low the front differentials also make constant clicking noise. Is it normal?

Clicking is not normal, might be a sign your birfs are on the way out. I'd have that checked.

 

[Ken C]

When I engage my cruiser's 4x4 low. It kind of jumps when its about to start running. when it starts running in 4x4 low the front differentials also make constant clicking noise. Is it normal?

Clicking can be a lot of things.

How do you know it is coming from the differentials?

 

[Kamran Khan]

Clicking can be a lot of things.

How do you know it is coming from the differentials?

Because It starts making clicking noise when i engage 4x4 low but in 4x4 High (FULL TIME 4WD) It don't make clicking noise. I may actually record it and post it on Youtube to share it here. It could be bearings I am not but sure but if it were bearing then why don't it make noise in all wheel drive.
I took it to mechanic and they said " Well I shouldn't be using 4x4 low on paved road" He didn't give me a solid answer on clicking noise.
But he did charge me for tightening the front hubs for both wheels. Actually I brought him the whole set for changing front knuckle bearings set but He said You know what, your cruiser bearings still good and can last for at least two more years. Even though there was play in front tires but he said it just need to get tightened.
He charged me 910$ labor for tightening front hubs and changing distributor O ring, crank seal and engine oil circulating pump seal.

 

[Ken C]

I don't think it is your birfs.

Try searching "low range clicking" or something like that.

 

[Howard705]

To make it more confusing you have a viscous coupler in the center diff- kind of in-between both modes- a limited center diff slip.