Jeep Wrangler 4High vs 4Low

[Frederic]

45 minutes ago, Zed said:

 

To cut the story short: Senior Marshal Fadi drives in 4Lo, and his convoy won the Desert Champions Trophy (I believe all in his convoy does the same; driving in 4Lo). That's 6 hours of non-stop driving in 4Lo and so yes you can get away with it.  His opinion on 4Lo here >> https://www.instagram.com/reel/Cm6VAp4q6lR/?igsh=ZnozYXVhbTNhZHNv

So I've re-geared 4x already and I've seen what's inside my transfer case + front & rear diffs. I would never drive 4Lo high speed in my Gear-Driven Transfer Case Land Cruiser, but I've driven a few times in 4Lo with my 5-speed Jeep with Chain-Driven Transfer Case... because Gear-Driven Transfer Case is only suitable for low-speed driving.  This is why there is No Generic Rule to 4LO: it primarily depends on the car and secondarily depends on the driver if he wishes to experiment with his car  

1) First front & rear to 4.88 gearing to cater for heavier tires on the Land Cruiser

2) Second opened my Transfer Case and re-geared the 4Lo gears to make 1:3 reduction in 4Lo only.

3) Third when installing ARB air lockers (carriers) I opened the front & rear differentials and notice the ring pattern signify that my differentials were not properly installed the first time. So I re-geared front & diff again, this time making sure proper break-in process is followed and triple-checking the backlash & preload of rings & pinions.

4) Finally I opened my Transfer Case again cos I was afraid same thing might happen to the Transfer Case as with the diffs. Then for fun & experiment I re-geared the 4Hi gearing in transfer case by simply changing 2 gears. This basically makes my 4Hi "spin more".

The 4.88 in front & rear diffs + the 10% underdrive in 4H gears Transfer Case = 5.3 final drive ratio so I don't need 4Lo for normal sand driving (even if my Transfer Case was Chain-Driven).

The whole Transfer Case system is just a GEAR REDUCTION mechanical device. And so a 1:4 Transfer Case Ratio for Rubicon just means the max speed in 4Lo is  1/4th of the max speed in 4Hi.  It's like driving slower than 1st Gear, but because there is no -1, -2, -3, -4  Shifter, the wizards invented Transfer Case to go Lower than Normal 1st Gear. Obviously there is no use of these lower gears in the asphalt / normal highway, but depending on car (should you wish to experiment), it may has some advantage in loose-traction areas like sand and slower-but-precision drives like rock-crawling.

 

So will 4Lo break your car? Judging by the simplicity of Gear Reduction concept, it probably won't. BUT older cars like my Land Cruiser have Gear-Driven Transfer Case whcih are not suitable for high-speed motion, so I agree with @Carnity Marshals here that you shouldn't drive in 4Lo with these kind of cars.  Newer cars with more transmission shifts and Chain-Driven Transfer Case have more flexibility... with the Chain TransferCase you can drive faster than with Noisy Gear-Driven TransferCase.  Most people who broke their transfer case in 4Lo most probably broke their Chain in the transfer case too, but for the adventurous who like to experiment with their cars, go ahead and drive in 4Lo... the theory has been laid out, and now it's time for practice 😁

 

Fantastic Fact-based explanation @Zed and this explains why from a club perspective we don't recommend driving in 4Lo it during the learning experience:

1. Every 4x4 is different, and it's hard to tell which 4x4 can survive constant driving in 4Lo and which not. So we keep it safe and advise people to read the manual of the vehicle.

2. During your initial learning experience (first 20-30 drives) it's much more important to learn the art of offroading in 4H and focus on enhancing the skills of reading the sand and lines to choose, and proper deflation. 

Once you reach a certain level where you are comfortable to start researching if 4LO is an option in your vehicle and you want to take the calculated risks/rewards, then it is solely your choice and not something that's enforced by a club.

[Gary F]

 Great post @Zed been thinking about this a lot recently and with 50 drives I think it’s time for some experimentation.

Driving the Jeep Gladiator Sandrunner (Mojave in USA) its already packing a few hundred kilos of extra weight vs a Wrangler between the bed, reinforced frame and larger axles.  
 

I often find on larger climbs in 4hi I’m running out of RPM in first and torque in second, with 31 inch tires.
 

The Mojave has a 2.71:1 transfer case allowing up to 70kmh speeds (50mph)

might be time to find tall dune for some experiments. 

[Mark B]

38 minutes ago, Gary F said:

 Great post @Zed been thinking about this a lot recently and with 50 drives I think it’s time for some experimentation.

Driving the Jeep Gladiator Sandrunner (Mojave in USA) its already packing a few hundred kilos of extra weight vs a Wrangler between the bed, reinforced frame and larger axles.  
 

I often find on larger climbs in 4hi I’m running out of RPM in first and torque in second, with 31 inch tires.
 

The Mojave has a 2.71:1 transfer case allowing up to 70kmh speeds (50mph)

might be time to find tall dune for some experiments. 

That is definitely worth exploring! That’s what she’s made for 😎😎

[Pavel Pashkovskiy]

1 hour ago, Gary F said:

 Great post @Zed been thinking about this a lot recently and with 50 drives I think it’s time for some experimentation.

Driving the Jeep Gladiator Sandrunner (Mojave in USA) its already packing a few hundred kilos of extra weight vs a Wrangler between the bed, reinforced frame and larger axles.  
 

I often find on larger climbs in 4hi I’m running out of RPM in first and torque in second, with 31 inch tires.
 

The Mojave has a 2.71:1 transfer case allowing up to 70kmh speeds (50mph)

might be time to find tall dune for some experiments. 

Did you tune your engine and gearbox? If not, you will not be able to climb in 4H or 4L. Offroading it is hobby and even lifestyle. Doing it, keeping in mind what happen with warranty or what says your insurance, means limiting yourself in most interesting part of it. If you want proper Jeep you must tune it. Minimum requirements are adjusting cooling system, tunning engine, tunning gearbox for faster switching. Out of than the minimum requirements for the engine tuning are proper air intake and exhaust. All above means bye-bye warranty. Ready for it? Go for it, you will not regret. Not ready? You can keep discussing about 4H, 4L... Nothing will help. You will never go outside of "elementary school".

[Frederic]

9 minutes ago, Pavel Pashkovskiy said:

Did you tune your engine and gearbox? If not, you will not be able to climb in 4H or 4L. Offroading it is hobby and even lifestyle. Doing it, keeping in mind what happen with warranty or what says your insurance, means limiting yourself in most interesting part of it. If you want proper Jeep you must tune it. Minimum requirements are adjusting cooling system, tunning engine, tunning gearbox for faster switching. Out of than the minimum requirements for the engine tuning are proper air intake and exhaust. All above means bye-bye warranty. Ready for it? Go for it, you will not regret. Not ready? You can keep discussing about 4H, 4L... Nothing will help. You will never go outside of "elementary school".

I’m happy to be an elementary school teacher and marshal based on your comments. You can comment all you like here on the forum but I would expect some common decency and respect for others instead of referring to stock Jeep drivers as elementary school.. 

A stock Jeep JL with 280hp can climb. Unless your reference benchmark is to go and climb Y60 hill or Moreeb from the front side, and in that case you’ll be going home with pink cheeks as when the locals arrive with their modified monsters, you’ll be realizing there is always someone bigger and better than you. Leave your ego behind and enjoy what you can do. 

 

[Pavel Pashkovskiy]

3 minutes ago, Frederic said:

I’m happy to be an elementary school teacher and marshal based on your comments. You can comment all you like here on the forum but I would expect some common decency and respect for others instead of referring to stock Jeep drivers as elementary school.. 

A stock Jeep JL with 280hp can climb. Unless your reference benchmark is to go and climb Y60 hill or Moreeb from the front side, and in that case you’ll be going home with pink cheeks as when the locals arrive with their modified monsters, you’ll be realizing there is always someone bigger and better than you. Leave your ego behind and enjoy what you can do. 

 

To talk about Jeep, you must have Jeep at first. To talk about proper Jeep you must have Jeep and first and make from it proper Jeep at second. Only people who passed all this steps can prove difference. 

Any stock car can climb something, even Toyota Corolla. 

[Gary F]

1 hour ago, Mark B said:

That is definitely worth exploring! That’s what she’s made for 😎😎

You’re on @Mark B  will need a clean dune and observers to record the results.

[Mark B]

Yeah definitely mate, couple of runs and you will know if it’s better or worse, I’ll try it in my sport too see what happens as an experiment 😁😁

[Zed]

2 hours ago, Gary F said:

 Great post @Zed been thinking about this a lot recently and with 50 drives I think it’s time for some experimentation.

Driving the Jeep Gladiator Sandrunner (Mojave in USA) its already packing a few hundred kilos of extra weight vs a Wrangler between the bed, reinforced frame and larger axles.  
 

I often find on larger climbs in 4hi I’m running out of RPM in first and torque in second, with 31 inch tires.
 

The Mojave has a 2.71:1 transfer case allowing up to 70kmh speeds (50mph)

might be time to find tall dune for some experiments. 

Congrats on reaching 50 drives @Gary F and your willingness to experiment to find your own driving style 👍🏻 . Please document it like this https://www.instagram.com/reel/C2SVhe5JgRU/?igsh=azVsa3B2c3VnZmN6 (middle of video he revealed it's 4Lo 3rd gear). Science says an experiment that can be repeated by others using the same tools means your paper is accepted by peer reviews and you've proven your point 😅

Pro Tip: start from 4Lo 3rd gear. ZF Transmission Triptronic is awesome that it will automatically cycle 1st & 2nd for you and hold in 3rd. Most Torque Curve diagrams say 3000-3500rpm is engine's peak torque, so when climbing, you want to find the best gear that's in that range and not go above 5000rpm (contrary to most beliefs, at 5000rpm you're actually losing torque).

Once you're in flatter areas, upshift to 4Lo 4th or above to keep rpm in the 2000-2500 rpm range to save petrol, and cool both engine & transmission. Downshift again before climbing. And when you're stuck, you're already in 4Lo so you can just shift to 1st or 2nd and do the blip-blip 🙂

*Also call me if you're going to choose Sweihan, Faya or Khatim for testing grounds, be happy to join if not busy ✌🏻

[Josh S]

For those driving in 4H, how often are you in First vs Second gear?