Full time rear diff locked when off roading in sand

[Luke K P]

@Julien Recanand I had a brief chat about using rear diff lock engaged in the sand full time. 

 

I've been using this recently and have seen some notes that Jeep sand runner has the same functionality when in desert offroad mode (up to 100kph)

What's the pros and cons of this? 

I note that this mode (on my vehicle at least) requires center diff engaged as well for 4WD (or just 2H), which is the default in sand mode. 

I did half my drive on Saturday in 4H + rear and centre locked, then half in 4A (unlocked centre and rear diff).

Could not perceive any difference to my driving experience in the large dunes in nahel.

Added page from manual from reference for locks and modes etc.

@ZedI'm sure you have some opinions on it?

Edited April 29 by Luke K P

[Zed]

@Luke K P @Julien Recan  please read my prev article on this if you haven't >> https://carnity.com/forums/topic/16736-diff-lock-simplified-center-rear-front-explained/

The Standard Order is Central Diff Lock > Rear Diff Lock >> and last Front Diff Lock.

Am sure there's a very technical reason for this, one involving blowing out diffs, but for shortcut let's just say this is how it's done in Mercedes G-Wagon and Toyota Land Cruiser 80, so let's follow Mercedes & Toyota engineers regarding this order of pressing the buttons  

Here's my take on your new orange Ford:

1. First check if your Center + Rear Diff Locks are automatically engaged when you switch to 4Lo. My Nissan Y62 Patrol did this, everytime I turned 4Lo, it automatically enganges Rear Diff Lock (thus also Center Diff Lock). My Jeep Grand Cherokee doesn't do this, so if I go 4Lo, it doesn't engage any diff locks.

How to test? You can't test on sand. In your parking space, turn on 4Lo then move forward 3 steps so it fully engages 4Lo. Then turn your steering wheel full-left (or full-right) and accelerate. If your tires are slipping or you hear screeching sound, means your rear diff is locked. Remember the purpose of Differential is so that left tyre and right tyre can spin at different speeds (which is needed for turning full-left/full-right mechanism)

 

2. If #1 doesn't make any sound means you are in 4Lo but in open diffs mode (no center and no rear diffs locked). Great, you can drive in 4Lo at high-speed to get more torque. 

 

3. Why would you ever want to drive with diff locks engaged at high speed ??? Read Point #1 above, the purpose of having differential is to allow left-tyre to spin faster/slower than right-tyre, which is needed for full-turn.

Yes in low-traction platform like soft sand and water, the tires still slip but they will not screech and make sound like in your concrete car parking or highway asphalt. But still, do you want to risk it? Example: you're riding on a ridge with soft sand with Center + Rear Diffs locked, then suddenly you have to make 90-degrees left-turn to exit the ridge riding. If the sand is hard (due to rain), now you're turning on a non low-traction platform. The tires will slip to make the turn, but because you're no longer in soft sand, you will be turning like a Rally Driver, with that drifting effect, which is fine on horizontal levelled plain areas (sabkhas), but on a ridge? Only the braves will risk it....

I've asked some "crazy" drivers why they turn-on Center Diff Lock when driving, and these are their reasons:

3.1.They want to drive in a STRAIGHT LINE very fast. Rally drivers do this. You can also try when you're climbing up in a straight line, but not when you're going up then decided to make a loop.

3.2 They want to drift when they're side-sloping, only doable with beadlocks. I've seen this in front of my eyes: so the car looks like fighting gravity, but in fact they are SLIDING horizontally with the nose facing 45-degrees up. Very cool for videos, but even I don't want to try that 😂

PS: we can do a 30-mins "testing session" after an official drive to test the various modes of your mighty Raptor 😁

 

 

Edited April 29 by Zed

[Julien Recan]

@Zed this is exactly what happened when I was cross-crossing. The back just slid when I tried to cross and ended up crested.

i (unwillingly, thought it was sensor issue) drove for 30 mins with rear diff lock on and while its not totally unmanageable, I clearly noticed the back was sliding a lot more anytime I was turning sharply. 
 

@Luke K P not sure how that compares to your experience, but from mine, I can’t really think wranglers are meant to be driven with it on 😁

[Luke K P]

17 minutes ago, Zed said:

@Luke K P @Julien Recan  please read my prev article on this if you haven't >> https://carnity.com/forums/topic/16736-diff-lock-simplified-center-rear-front-explained/

The Standard Order is Central Diff Lock > Rear Diff Lock >> and last Front Diff Lock.

Am sure there's a very technical reason for this, one involving blowing out diffs, but for shortcut let's just say this is how it's done in Mercedes G-Wagon and Toyota Land Cruiser 80, so let's follow Mercedes & Toyota engineers regarding this order of pressing the buttons  

Here's my take on your new orange Ford:

1. First check if your Center + Rear Diff Locks are automatically engaged when you switch to 4Lo. My Nissan Y62 Patrol did this, everytime I turned 4Lo, it automatically enganges Rear Diff Lock (thus also Center Diff Lock). My Jeep Grand Cherokee doesn't do this, so if I go 4Lo, it doesn't engage any diff locks.

How to test? You can't test on sand. In your parking space, turn on 4Lo then move forward 3 steps so it fully engages 4Lo. Then turn your steering wheel full-left (or full-right) and accelerate. If your tires are slipping or you hear screeching sound, means your rear diff is locked. Remember the purpose of Differential is so that left tyre and right tyre can spin at different speeds (which is needed for turning full-left/full-right mechanism)

 

2. If #1 doesn't make any sound means you are in 4Lo but in open diffs mode (no center and no rear diffs locked). Great, you can drive in 4Lo at high-speed to get more torque. 

 

3. Why would you ever want to drive with diff locks engaged at high speed ??? Read Point #1 above, the purpose of having differential is to allow left-tyre to spin faster/slower than right-tyre, which is needed for full-turn.

Yes in low-traction platform like soft sand and water, the tires still slip but they will not screech and make sound like in your concrete car parking or highway asphalt. But still, do you want to risk it? Example: you're riding on a ridge with soft sand with Center + Rear Diffs locked, then suddenly you have to make 90-degrees left-turn to exit the ridge riding. If the sand is hard (due to rain), now you're turning on a non low-traction platform. The tires will slip to make the turn, but because you're no longer in soft sand, you will be turning like a Rally Driver, with that drifting effect, which is fine on horizontal levelled plain areas (sabkhas), but on a ridge? Only the braves will risk it....

I've asked some "crazy" drivers why they turn-on Center Diff Lock when driving, and these are their reasons:

3.1.They want to drive in a STRAIGHT LINE very fast. Rally drivers do this. You can also try when you're climbing up in a straight line, but not when you're going up then decided to make a loop.

3.2 They want to drift when they're side-sloping, only doable with beadlocks. I've seen this in front of my eyes: so the car looks like fighting gravity, but in fact they are SLIDING horizontally with the nose facing 45-degrees up. Very cool for videos, but even I don't want to try that 😂

PS: we can do a 30-mins "testing session" after an official drive to test the various modes of your mighty Raptor 😁

 

 

Thanks @Zed.
Indeed I have checked that sand mode (4H) does engage rear difflock right away. Can turn it off and keep it off.

4L does not automatically switch it on.. 4L becomes manual on and off.

Given your descriptions above.. think maybe the 'sand mode' ( 4H + diff lock ) is aimed at american baja type flat sand desert driving rather than up and over of dunes.... ie lots of drifting on fairly level ground.

5 minutes ago, Julien Recan said:

@Zed this is exactly what happened when I was cross-crossing. The back just slid when I tried to cross and ended up crested.

i (unwillingly, thought it was sensor issue) drove for 30 mins with rear diff lock on and while its not totally unmanageable, I clearly noticed the back was sliding a lot more anytime I was turning sharply. 
 

@Luke K P not sure how that compares to your experience, but from mine, I can’t really think wranglers are meant to be driven with it on 😁

yeah the cresting whilst turning over it @Julien Recan left me thinking about this all weekend.

Edited April 29 by Luke K P

[RiadJL]

26 minutes ago, Zed said:

@Luke K P @Julien Recan  please read my prev article on this if you haven't >> https://carnity.com/forums/topic/16736-diff-lock-simplified-center-rear-front-explained/

The Standard Order is Central Diff Lock > Rear Diff Lock >> and last Front Diff Lock.

Am sure there's a very technical reason for this, one involving blowing out diffs, but for shortcut let's just say this is how it's done in Mercedes G-Wagon and Toyota Land Cruiser 80, so let's follow Mercedes & Toyota engineers regarding this order of pressing the buttons  

Here's my take on your new orange Ford:

1. First check if your Center + Rear Diff Locks are automatically engaged when you switch to 4Lo. My Nissan Y62 Patrol did this, everytime I turned 4Lo, it automatically enganges Rear Diff Lock (thus also Center Diff Lock). My Jeep Grand Cherokee doesn't do this, so if I go 4Lo, it doesn't engage any diff locks.

How to test? You can't test on sand. In your parking space, turn on 4Lo then move forward 3 steps so it fully engages 4Lo. Then turn your steering wheel full-left (or full-right) and accelerate. If your tires are slipping or you hear screeching sound, means your rear diff is locked. Remember the purpose of Differential is so that left tyre and right tyre can spin at different speeds (which is needed for turning full-left/full-right mechanism)

 

2. If #1 doesn't make any sound means you are in 4Lo but in open diffs mode (no center and no rear diffs locked). Great, you can drive in 4Lo at high-speed to get more torque. 

 

3. Why would you ever want to drive with diff locks engaged at high speed ??? Read Point #1 above, the purpose of having differential is to allow left-tyre to spin faster/slower than right-tyre, which is needed for full-turn.

Yes in low-traction platform like soft sand and water, the tires still slip but they will not screech and make sound like in your concrete car parking or highway asphalt. But still, do you want to risk it? Example: you're riding on a ridge with soft sand with Center + Rear Diffs locked, then suddenly you have to make 90-degrees left-turn to exit the ridge riding. If the sand is hard (due to rain), now you're turning on a non low-traction platform. The tires will slip to make the turn, but because you're no longer in soft sand, you will be turning like a Rally Driver, with that drifting effect, which is fine on horizontal levelled plain areas (sabkhas), but on a ridge? Only the braves will risk it....

I've asked some "crazy" drivers why they turn-on Center Diff Lock when driving, and these are their reasons:

3.1.They want to drive in a STRAIGHT LINE very fast. Rally drivers do this. You can also try when you're climbing up in a straight line, but not when you're going up then decided to make a loop.

3.2 They want to drift when they're side-sloping, only doable with beadlocks. I've seen this in front of my eyes: so the car looks like fighting gravity, but in fact they are SLIDING horizontally with the nose facing 45-degrees up. Very cool for videos, but even I don't want to try that 😂

PS: we can do a 30-mins "testing session" after an official drive to test the various modes of your mighty Raptor 😁

 

 

Interesting..

 

I haven't been able to climb up Iftar bowl's center face so far. My impression was the wheels spend too much time in the air because of all the tire tracks in the sand there and so I'm not able to put down enough power. Do you think diff locks would help in this case? or sway bar disconnect?  

[Zed]

4 minutes ago, RiadJL said:

Interesting..

I haven't been able to climb up Iftar bowl's center face so far. My impression was the wheels spend too much time in the air because of all the tire tracks in the sand there and so I'm not able to put down enough power. Do you think diff locks would help in this case? or sway bar disconnect?  

hi @RiadJL each scenario is different, tag me if you're joining next Iftar Bowl drive and will be happy to check your various configuration. But please go through these first before jumping to diff lock:

1. Lower your psi. I had trouble climbing some parts of Lady Dune, but was able to climb after deflating all tires to 10 psi. Of course if you don't have thick sidewalls, safest is to stick to 12 psi (now you have a reason to get taller tires that have "70" or "75" in the middle like 265/70/17)

2. Try in 4Lo but higher gears (e.g.  4Lo + 3rd gear or 4Lo + 4th gear). This will give you lots of torque but also some speed.

3. If you're tires are jumping in the air and the terrain is bumpy, you need firmer shocks (which is perfect for offroad and bumps but too stiff for daily driving).

4. If 1+2+3 above are done but still "no power", you can try Center Diff Lock only

5. If 1+2+3+4 above are done and still "no power", allow me to drive your car.

6. If 1-5 are done and still "no power", let's discuss buying another car  

 

 

[RiadJL]

7 minutes ago, Zed said:

hi @RiadJL each scenario is different, tag me if you're joining next Iftar Bowl drive and will be happy to check your various configuration. But please go through these first before jumping to diff lock:

1. Lower your psi. I had trouble climbing some parts of Lady Dune, but was able to climb after deflating all tires to 10 psi. Of course if you don't have thick sidewalls, safest is to stick to 12 psi (now you have a reason to get taller tires that have "70" or "75" in the middle like 265/70/17)

2. Try in 4Lo but higher gears (e.g.  4Lo + 3rd gear or 4Lo + 4th gear). This will give you lots of torque but also some speed.

3. If you're tires are jumping in the air and the terrain is bumpy, you need firmer shocks (which is perfect for offroad and bumps but too stiff for daily driving).

4. If 1+2+3 above are done but still "no power", you can try Center Diff Lock only

5. If 1+2+3+4 above are done and still "no power", allow me to drive your car.

6. If 1-5 are done and still "no power", let's discuss buying another car  

 

 

Yeah, I get the feeling it's the shocks. Looking to upgrade soon.. Will try out 1+2 next time I'm down there

 

Don't think the car's the problem - probably the driver 🤪

[Zed]

32 minutes ago, Luke K P said:

Given your descriptions above.. think maybe the 'sand mode' ( 4H + diff lock ) is aimed at american baja type flat sand desert driving rather than up and over of dunes.... ie lots of drifting on fairly level ground.

@Luke K P @Julien Recan check out this recent Dakkar Rally "amazing shot" video, the car is "fighting gravity" on a side-slope.  Center Diff Lock + Rear Diff Locks will help here:

• Center Diff Lock will ensure both front axle + rear axle spins at same speed. 50-50, not 40:60, not 30:70. 50:50 means better traction because if your rear tires are slipping, front tires still have 50% power to pull (assuming the sand allows it).
• Rear Diff Lock will ensure rear-left + rear-right tires are always spinning. What if you hit a small stone and your rear-left tire is in the air? Without rear-diff-lock, this tire in the air will spin and the tire on the ground will stop spinning (at least momentarily until all tires land on the sand again). BUT this driver has to go down in a controlled manner and not full 90-degrees down.

[Luke K P]

10 minutes ago, Zed said:

@Luke K P @Julien Recan check out this recent Dakkar Rally "amazing shot" video, the car is "fighting gravity" on a side-slope.  Center Diff Lock + Rear Diff Locks will help here:

• Center Diff Lock will ensure both front axle + rear axle spins at same speed. 50-50, not 40:60, not 30:70. 50:50 means better traction because if your rear tires are slipping, front tires still have 50% power to pull (assuming the sand allows it).
• Rear Diff Lock will ensure rear-left + rear-right tires are always spinning. What if you hit a small stone and your rear-left tire is in the air? Without rear-diff-lock, this tire in the air will spin and the tire on the ground will stop spinning (at least momentarily until all tires land on the sand again). BUT this driver has to go down in a controlled manner and not full 90-degrees down.

That's my drifting style on the 1m tall ridge I got stuck on on Saturday 😎🤣

 

Thanks for all the examples and info@Zed 🙏🙏🙏

 

Edited April 29 by Luke K P