Diff locks question

[To]

a question about diff locks. I 've had three cases of getting badly stuck in a 4x4 over the years. None of the vehicles has lockers: 1) a 1962 Land Rover IIA when I got the differentials up on hard pack snow on the side of a bare road. The right side tires on bare asphalt, the two left side tires on snow. I the wheels on snow just spun and I could nto move until I dug out the the ice/snow that was holding up the differentials.
2) A 2012 VW Touareg TDI, again in deep soft snow with a layer of hard pack half way down that supported the differentials
3) a 2007 LR3 in deep wet clay. underbody slightly grounded and two wheels on one side would spin. Had to tow it out.
The tires were all seasons with fairly aggressive treads. Getting aggressive tread mud tires would not be an answer since they would not be appropriate for 80% of the vehicles use (yes, my IIA was a daily driver for a year).
Do folks think front+read locking differentials have helped in 1) or 2)
Suggestions welcomed

Center differential lock activated, one wheel spins on each axle-stop. An axle locker engaged, then one wheel has grip. This may be enough to get the car moving again. The second axle locker is activated, then two wheels have grip again and the car will definitely be afloat again on its own. However, a lot depends on the surface.

 

[Tazzieman]

Once the axles and diffs start acting like bulldozer blades , you're in shovel territory!

 

[Jean Mercier]

Clay is indeed the worst situation, especially if there is also some water "supply", then even digging doesn't help. Because digging means automatic refill with fresh very wet clay, making the situation even worse.
I got once stuck like this in Tunisia, only nose and front wheels were inside the clay, rear wheels were still on hard ground. Clay also acts like "suction" or "glue". I had to be towed out!

But indeed, the most important thing is locking the differentials in advance, once you think the terrain gets difficult, and advancing at a steady speed, not necessarily fast.
And stop trying to go on once the wheels are spinning, because you are only digging a hole. Try to go backwards, and give up or try again changing a little bit the position on the track (moving right or left according to the difficulties of the terrain).

 

[DDG]

A fun and easy way to learn to use locking diffs is with an ATV. While it’s not entirely analogous; it’s possible to learn the use cases on the ATV. It’s also a lot easier to yank the smaller machine out when necessary. Even with practice I find myself reaching for traction mats or a shovel more often than not. I am not a seasoned off-roader by any stretch of the imagination. Recovery seems to be a big part of the hobby

 

[Jean Mercier]

And what is an ATV? I hate abbreviations

 

[Hannes01]

All terrain vehicle. I think means Quad

 

[Tazzieman]

All terrain vehicle. I think means Quad

Aka quads in my neck of the woods , partly due to the injuries which result in quadriplegia.
Far too many getting flipped.

 

[AnD3rew]

Aka quads in my neck of the woods , partly due to the injuries which result in quadriplegia.
Far too many getting flipped.

Lots of deaths too, personally know of two families who have lost people to quads. Mostly now trending towards the Can Am style sit in side by sides with a proper roof.

 

[DDG]

Yes. There is no question that all terrain vehicles are dangerous and a bad idea in general. Living on a couple rural acres, I sure do find them useful though. Hopefully used with caution and respect for what could happen, I’ll get away with using them for a few more years.

 

[Scott_USA]

Regarding the center diff lock.....I saw one video where the CDL was engaged while the vehicle was moving. Now that some are driving production vehicles is there an upper speed limit specified for this capability? This would be desirable when on road and transitioning from dry to icy or snowy conditions?

 

[TheDocAUS]

Regarding the center diff lock.....I saw one video where the CDL was engaged while the vehicle was moving. Now that some are driving production vehicles is there an upper speed limit specified for this capability? This would be desirable when on road and transitioning from dry to icy or snowy conditions?

Apparently less than 15kph, watch this video.

View: https://youtu.be/bfy5SAIkiC0

 

[Scott_USA]

Apparently 15kph, watch this video.

View: https://youtu.be/bfy5SAIkiC0

Thanks for sharing this but it doesn't quite answer my question. The 15kph he mentions is for engaging the rear or front differentials after the CDL was engaged when he selected low range. There is likely a different more forgiving speed that allows you to go from 4WD open diff mode (on pavement) to 4WD High mode off pavement. In my jeep jk, you can engage 4WD High up to speeds of 55mph. Of course the jeep is a part time 4wD and the IG is permanent 4WD. I did leave a comment on the video you provided so hopefully he'll respond. It should be easy to find in the manual.

 

[DaveB]

Thanks for sharing this but it doesn't quite answer my question. The 15kph he mentions is for engaging the rear or front differentials after the CDL was engaged when he selected low range. There is likely a different more forgiving speed that allows you to go from 4WD open diff mode (on pavement) to 4WD High mode off pavement. In my jeep jk, you can engage 4WD High up to speeds of 55mph. Of course the jeep is a part time 4wD and the IG is permanent 4WD. I did leave a comment on the video you provided so hopefully he'll respond. It should be easy to find in the manual.

I was under the impression that the Jeep JK is standard as 2WD only (front wheels driven??) and uses a chain driven transfer box to engage 4H locked or 4L locked.
There is no option for 4wd unlocked centre diff.
This means that you can only go into 4wd when on a slippery low traction surface and when the front and rear wheels are travelling at the same speed and no wheels have lost traction.
So don't wait until you hit the slippery stuff to engage but as you are now in locked drive then don't engage it too soon on the hard stuff.
To go into 4LO you have to be in Neutral and coasting??????
So if you get stuck in 4 high and decide 4 low will get you out you are potentially going to be in a lot of trouble.
Interesting as well the N or Neutral position on the transfer case completely disconnects the drive to either axle and the vehicle can roll forward or backward freely even when the gearbox is in gear or park for an auto. Better make sure that handbrake is on.

 

[Scott_USA]

I was under the impression that the Jeep JK is standard as 2WD only (front wheels driven??) and uses a chain driven transfer box to engage 4H locked or 4L locked.
There is no option for 4wd unlocked centre diff.
This means that you can only go into 4wd when on a slippery low traction surface and when the front and rear wheels are travelling at the same speed and no wheels have lost traction.
So don't wait until you hit the slippery stuff to engage but as you are now in locked drive then don't engage it too soon on the hard stuff.
To go into 4LO you have to be in Neutral and coasting??????
So if you get stuck in 4 high and decide 4 low will get you out you are potentially going to be in a lot of trouble.
Interesting as well the N or Neutral position on the transfer case completely disconnects the drive to either axle and the vehicle can roll forward or backward freely even when the gearbox is in gear or park for an auto. Better make sure that handbrake is on.

View attachment 7808316View attachment 7808318View attachment 7808317

Yes, the Jeep Wrangler JK is part time 4wd. So when not engaged in 4 High it is in 2wd (rear wheel). It does not have a center diff per se but the transfer case serves a similar function as a CDL when shifting into 4 High. So, you only want to shift into 4 High in low traction situations but you can do this on the fly when transitioning between surfaces. So at least you don't have to stop. And yes, the transfer case has a neutral which allows you to flat tow the jeep without any other mechanical adjustments. I suppose you could find yourself where engaging 4 low could be a challenge. Planning ahead is always a good idea. My JK also has front and rear lockers and detachable sway bar. All that said, the newer JLs do offer a 4wd mode where the transfer case is not engaged and can operate on pavement, so this mode is more like the Grenadier with an open CDL. The JL still operates in 2wd for a little better gas mileage.

 

[Tazzieman]

Planning ahead is always a good idea.

In my 50 yo Series Landy I tend to plan the day before. Braking , steering and traction aids.

 

[Ausadier]

Rookie question if anyone can assist. Context - I am not a experienced 4wd guy.
I see the IG has centre diff lock when you put it in High lock or low lock.
Would this diff lock not suffice in most sketchier 4wd instances eg prevent torque to free spinning wheel etc?
As a result
1. Can you survive without the front and rear lockers (if not going to hard core 4wd)
2. What extra bonusses or situations does the front and rear option give you
Thanks for any insight

 

[bigleonski]

Simple answer is that yes, CDL and high/low range will be all you need if you are not doing anything too complicated.

The best thing you can buy yourself is a decent 4wd course with a qualified off road instructor. They will show you what your vehicle can and cannot do, and teach you how to use it in various offroad situations. And they’ll help you buy recovery gear that will be appropriate for where you are likely to take your vehicle. Or join a 4wd club if they exist where you are.

 

[Michael H.]

Simple answer is that yes, CDL and high/low range will be all you need if you are not doing anything too complicated.

The best thing you can buy yourself is a decent 4wd course with a qualified off road instructor. They will show you what your vehicle can and cannot do, and teach you how to use it in various offroad situations. And they’ll help you buy recovery gear that will be appropriate for where you are likely to take your vehicle. Or join a 4wd club if they exist where you are.

Spot on answer.

 

[globalgregors]

Rookie question if anyone can assist. Context - I am not a experienced 4wd guy.
I see the IG has centre diff lock when you put it in High lock or low lock.
Would this diff lock not suffice in most sketchier 4wd instances eg prevent torque to free spinning wheel etc?
As a result
1. Can you survive without the front and rear lockers (if not going to hard core 4wd)

Yes, most certainly. We went around the world - mountains, swamps, beaches and deserts - with only CDL (and LRs Terrain system) and never needed a recovery, so for sure you’ll be fine if you stay attentive to where you’re about to drive.

2. What extra bonusses or situations does the front and rear option give you

Think of the CDL as keeping you moving forward if either the front or the rear wheels have grip.
FDL/RDL keep you moving if either the left side or the right side have grip.

In very technical terrain, this can mean that one can slow down and take a more deliberate approach.

Picture situations where the surface is patchy and very slippery, or so uneven that you might have two wheels off the ground diagonally. Arguably one would almost need to seek out such environments.

As @bigleonski indicates, without it the only real difference may come down to how often one would need to recover/intervene with shovel, maxtrax etc. Which if you’re not on the clock is maybe all part of the fun.

Diff locks add a little weight and complexity, but in this rather simple implementation I don’t think this should be a decision factor.

The only other consideration is that in Oz the presence of diff locks is presumed to impact resale value/desirability.

Thanks for any insight

Welcome to the forum!

 

[Michael H.]

Yes, most certainly. We went around the world - mountains, swamps, beaches and deserts - with only CDL (and LRs Terrain system) and never needed a recovery, so for sure you’ll be fine if you stay attentive to where you’re about to drive.

Think of the CDL as keeping you moving forward if either the front or the rear wheels have grip.
FDL/RDL keep you moving if either the left side or the right side have grip.

In very technical terrain, this can mean that one can slow down and take a more deliberate approach.

Picture situations where the surface is patchy and very slippery, or so uneven that you might have two wheels off the ground diagonally. Arguably one would almost need to seek out such environments.

As @bigleonski indicates, without it the only real difference may come down to how often one would need to recover/intervene with shovel, maxtrax etc. Which if you’re not on the clock is maybe all part of the fun.

The only other consideration is that in Oz the presence of diff locks is presumed to impact resale value/desirability.

Welcome to the forum!

Another excellent response.