UZJ100 4x4, 4wd system explained

[Jody Highroller]

http://m.youtube.com/watch?v=JHRh_BrLTKk

Video showing Rubicon sytem ...would love to see this for my land cruiser

So the question becomes does the 98-99 TLC have open diff or limited slip when CDL is engaged and in 4 Low?? Because if there is not some sort of limited slip or brake system assist prior to having to lock the RR locker, that means I can be splitting power equality in the rear, however, the front is open and when one front wheel slips the other front wheel is dead and it essentially becomes positive traction Rwd only.

 

[codertimt]

Very true. That's why I think his post could be technically wrong. I may not ever find real engineering data on how this 98-99 works. Even a Subaru with symmetrical 4wd system sends power to the wheels that are not spin whenever the others lose traction..

The link I posted is am excellent 4wd drive test. They use a roller ramp to prove that toyota and Honda "full-time 4WD systems are worthless. If the poster who "simplified it" is correct I will be getting a different vehicle, very soon. Btw, I've had my off road with these a MTR retreads and I've not been stuck. But where I plan on going is the roughest test thus far.

Um, so you do realize that your friends "real 4x4" ZJ is going to completely fail a roller ramp also unless it has aftermarket lockers. The only difference between your full time 4WD and the ZJ is he has the ability to run in 2wd Hi. I think a '97 should have a NP242 transfer case. He will have 2HI, 4HI Full Time(just like our center diff unlocked) 4HI Part Time(center diff locked) and 4LO. As said, unless he has aftermarket lockers, diff wise, it could have came with a rear limited slip, but will have no other traction aids such as lockers or electronic traction control stock. So technically in that regards, you "win" based on your rear locker.

Back to a roller test, most four wheel drive vehicles on the road today will fail that test. There are some very sophisticated traction control systems(and I'm sure they are always getting better) that can properly deal with such a traction situation, not sure how our ATRAC would do...also ATRAC acts differently in 4HI versus 4LO, so an AWD car versus our Full time 4WD could have different results.

You're particular vehicle would actually do will on such a test since you have the rear locker...with it engaged you will get a 50/50 split to the rear wheels and should keep moving just fine.

Anyway, as has been stated already, there is nothing at all complicated going on in your '98. You have no electronic traction control, so your operation modes...

4HI/Open Front/Open Rear/Open Center

In this mode you have equal power split to all wheels given adequate traction. RF can turn at a different rate than LF because of open front diff. RR can turn at different rate than LR because of open rear diff. Front can turn at different rate than Rear because of Open center diff. This allows on pavement turning and cornering without any binding or damage to drivetrain. The caveat is that when a tire no longer has adequate traction it will end up spinning and the other tires will no longer be able to provide momentum. Everyone says that the tire with the least traction receives all the power, and that an easy and practical way to look at it. It actually has to do with torque multiplication and how much work is able to be done and there is math involved...but you can pretty much just say that the wheel with the least traction gets the power...

4HI or 4LO/Open Front/Open Rear/Locked Center
Same as above except while turning in a high traction situation, the front tires cannot turn at a different rate as the rear tires and you can end up damaging the transfer case. In practice the difference is that you are always going to get a 50/50 power split front to rear. So if one front tire completely loses traction(and "gets the power" as outlined above). You still get 50% of your power going to the rear to keep momentum.

4HI or 4LO/Open Front Locked Rear/Locked Center
Same as above execpt while turning in high traction situation the LR cannot turn at a different rate as the RR, so generally you will end up with one tire sliding or "barking" in a tight turn on pavement. Could damage diff, but generally here the tire will still slip before diff damage. In practice, the difference is in a situation like the roller test, you get a 50/50 left/right split on the rear...and hopefully still can keep momentum.

So nothing complicated here. You have a traditional 4WD system with a rear locker. No fancy traction control to help or hinder...just a mechanical locker...just like the Rubicon. You just don't have one in the front...$1500 or so can fix that...

Last notes....

Something that might confuse some people is full time 4WD versus AWD. In general AWD doesn't have low range gearing. Full time 4WD does.

Don't get caught up with some unrealistic test like a roller test or ice hill test which puts one set of tires in 0 traction and the other in full traction...your not likely to see such a situation very often if at all. Most off-road low traction situations are very dynamic and allow you to find a way to place tires where than can provide traction to the ground most effectively. Obviously there are times where you cannot...those are the times where the rear locker comes in to help...or where your friends ZJ's solid front axle can provide more wheel travel and provide both front wheels with some traction.

So, not sure if this post will be helpful, but basically all I want to say is don't freak out because you don't have triple lockers. I have an open/open XJ that will go many, many places. It's all about knowing your vehicle and where to place the tires...

 

[RKFZJ80]

Not to beat a dead horse here, but a ZJ with a V-8 has no 2wd option " full time" 4 wheel only, a 4.0 liter 6 would have 2wd as an option. I had a 1996 ZJ with the V-8 & can say it is the only rig that I have ever owned that worked as well in the snow as my (former) FZJ80.

 

[Jody Highroller]

Um, so you do realize that your friends "real 4x4" ZJ is going to completely fail a roller ramp also unless it has aftermarket lockers. The only difference between your full time 4WD and the ZJ is he has the ability to run in 2wd Hi. I think a '97 should have a NP242 transfer case. He will have 2HI, 4HI Full Time(just like our center diff unlocked) 4HI Part Time(center diff locked) and 4LO. As said, unless he has aftermarket lockers, diff wise, it could have came with a rear limited slip, but will have no other traction aids such as lockers or electronic traction control stock. So technically in that regards, you "win" based on your rear locker.

Back to a roller test, most four wheel drive vehicles on the road today will fail that test. There are some very sophisticated traction control systems(and I'm sure they are always getting better) that can properly deal with such a traction situation, not sure how our ATRAC would do...also ATRAC acts differently in 4HI versus 4LO, so an AWD car versus our Full time 4WD could have different results.

You're particular vehicle would actually do will on such a test since you have the rear locker...with it engaged you will get a 50/50 split to the rear wheels and should keep moving just fine.

Anyway, as has been stated already, there is nothing at all complicated going on in your '98. You have no electronic traction control, so your operation modes...

4HI/Open Front/Open Rear/Open Center

In this mode you have equal power split to all wheels given adequate traction. RF can turn at a different rate than LF because of open front diff. RR can turn at different rate than LR because of open rear diff. Front can turn at different rate than Rear because of Open center diff. This allows on pavement turning and cornering without any binding or damage to drivetrain. The caveat is that when a tire no longer has adequate traction it will end up spinning and the other tires will no longer be able to provide momentum. Everyone says that the tire with the least traction receives all the power, and that an easy and practical way to look at it. It actually has to do with torque multiplication and how much work is able to be done and there is math involved...but you can pretty much just say that the wheel with the least traction gets the power...

4HI or 4LO/Open Front/Open Rear/Locked Center
Same as above except while turning in a high traction situation, the front tires cannot turn at a different rate as the rear tires and you can end up damaging the transfer case. In practice the difference is that you are always going to get a 50/50 power split front to rear. So if one front tire completely loses traction(and "gets the power" as outlined above). You still get 50% of your power going to the rear to keep momentum.

4HI or 4LO/Open Front Locked Rear/Locked Center
Same as above execpt while turning in high traction situation the LR cannot turn at a different rate as the RR, so generally you will end up with one tire sliding or "barking" in a tight turn on pavement. Could damage diff, but generally here the tire will still slip before diff damage. In practice, the difference is in a situation like the roller test, you get a 50/50 left/right split on the rear...and hopefully still can keep momentum.

So nothing complicated here. You have a traditional 4WD system with a rear locker. No fancy traction control to help or hinder...just a mechanical locker...just like the Rubicon. You just don't have one in the front...$1500 or so can fix that...

Last notes....

Something that might confuse some people is full time 4WD versus AWD. In general AWD doesn't have low range gearing. Full time 4WD does.

Don't get caught up with some unrealistic test like a roller test or ice hill test which puts one set of tires in 0 traction and the other in full traction...your not likely to see such a situation very often if at all. Most off-road low traction situations are very dynamic and allow you to find a way to place tires where than can provide traction to the ground most effectively. Obviously there are times where you cannot...those are the times where the rear locker comes in to help...or where your friends ZJ's solid front axle can provide more wheel travel and provide both front wheels with some traction.

So, not sure if this post will be helpful, but basically all I want to say is don't freak out because you don't have triple lockers. I have an open/open XJ that will go many, many places. It's all about knowing your vehicle and where to place the tires...

Excellent post, I really appreciate your time. You answered most of my technical an operational inquiries. The only thing that still concerns me is having the open diff in the front, which can be addressed with the locker. I would love to be locked all around, but with a vehicle with IFS, I'm not sure if I wouldn't be Better off going with a FJ60 build and putting Dana axles and lockers or going with a rubicon wouldn't be a better option. But, the 100 series looks great, it rises awesome and the engine is legendary in reliability.

I guess ultimately this thread has been a comparison in my 99 TLC vs 97 ZJ Laredo 5.2. I doubt seriously he has lockers unless that was an option then. I think that vehicle has the select or quadra trac with the Brake Diff locker or brake assist mechanism. It may have limited slip with the BDL acting as a semi locker. Not sure but I can tell you, that son bitch is a billy goat in the mountain.

 

[RKFZJ80]

Excellent post, I really appreciate your time. You answered most of my technical an operational inquiries. The only thing that still concerns me is having the open diff in the front, which can be addressed with the locker. I would love to be locked all around, but with a vehicle with IFS, I'm not sure if I wouldn't be Better off going with a FJ60 build and putting Dana axles and lockers or going with a rubicon wouldn't be a better option. But, the 100 series looks great, it rises awesome and the engine is legendary in reliability. I guess ultimately this thread has been a comparison in my 99 TLC vs 97 ZJ Laredo 5.2. I doubt seriously he has lockers unless that was an option then. I think that vehicle has the select or quadra trac with the Brake Diff locker or brake assist mechanism. It may have limited slip with the BDL acting as a semi locker. Not sure but I can tell you, that son bitch is a billy goat in the mountain.

97 ZJ 5.2 would be the quadra-trac fulltime 4x4, NV 249 tcase,I don't think it had any traction aids in the front (Dana 30), but the rear (dana 44) has limited slip. I had the same rig and agree, that thing was amazing in the snow, could hardly ever get stuck, I had to work at it!

 

[codertimt]

Not to beat a dead horse here, but a ZJ with a V-8 has no 2wd option " full time" 4 wheel only, a 4.0 liter 6 would have 2wd as an option. I had a 1996 ZJ with the V-8 & can say it is the only rig that I have ever owned that worked as well in the snow as my (former) FZJ80.

Sorry for the misinformation...not terribly familiar with the ZJs.

Excellent post, I really appreciate your time. You answered most of my technical an operational inquiries. The only thing that still concerns me is having the open diff in the front, which can be addressed with the locker. I would love to be locked all around, but with a vehicle with IFS, I'm not sure if I wouldn't be Better off going with a FJ60 build and putting Dana axles and lockers or going with a rubicon wouldn't be a better option. But, the 100 series looks great, it rises awesome and the engine is legendary in reliability.

I guess ultimately this thread has been a comparison in my 99 TLC vs 97 ZJ Laredo 5.2. I doubt seriously he has lockers unless that was an option then. I think that vehicle has the select or quadra trac with the Brake Diff locker or brake assist mechanism. It may have limited slip with the BDL acting as a semi locker. Not sure but I can tell you, that son bitch is a billy goat in the mountain.

So, as mentioned not terribly familiar with the ZJs, but what I'm reading show that a '97 should have any kind of electronic traction control. Could have limited slip, but that would be about it. A ZJ has a weight advantage and the solid front axle can definitely help keep traction to the front in some situations.

But the 100, should be fine overall. It's not a solid axle crawler, so there will be situations where the IFS is going to lift a tire and you will lose traction on the front...hopefully it will be momentary and the rear locker will be all that is needed to maintain momentum... It's all matter of what you truly need for your environment. A built 60 will be able to handle tougher trails than your average 100. A flexy, built Rubicon even more so. But unless your hunting lease is on a rock crawling course, most likely the 100 will be just fine...and quite a bit more comfortable than a ZJ...no offense to the ZJ owners, but I know my LX is a whole heck of a lot more comfy than my XJ...

 

[RKFZJ80]

Sorry for the misinformation...not terribly familiar with the ZJs. So, as mentioned not terribly familiar with the ZJs, but what I'm reading show that a '97 should have any kind of electronic traction control. Could have limited slip, but that would be about it. A ZJ has a weight advantage and the solid front axle can definitely help keep traction to the front in some situations. But the 100, should be fine overall. It's not a solid axle crawler, so there will be situations where the IFS is going to lift a tire and you will lose traction on the front...hopefully it will be momentary and the rear locker will be all that is needed to maintain momentum... It's all matter of what you truly need for your environment. A built 60 will be able to handle tougher trails than your average 100. A flexy, built Rubicon even more so. But unless your hunting lease is on a rock crawling course, most likely the 100 will be just fine...and quite a bit more comfortable than a ZJ...no offense to the ZJ owners, but I know my LX is a whole heck of a lot more comfy than my XJ...

You had good info, no doubt that I really was impressed with my ZJ, but given the choice I would take the 100 over the ZJ any day. The ZJ is a step up comfort wise vs your XJ. Sounds to me like you need a good triple-locked 80 best of both worlds!
Cheers!

 

[RobRed]

I'll just go ahead and leave this here.



Spotted on my way to work.

 

[stonepa]

How about this idea? Load up 4 of your buddies, a couple of dogs, and some shot guns and drive the trail in your truck. If you get stuck, pick a better line next time. All this academic stuff is giving me a headache

 

[Ole Colony]

I agree with this post. The only way to shut them up is to show them. Even in the cruiser community the 100 is underestimated. At southern cruiser crawl the 60 and 80 guys in my club were impressed with my 100 on some level 3 trails.

 

[Jody Highroller]

I understand that the tech data and science behind 4x4 systems bores some. But for me and many others it is THE critical requirement of choosing a vehicle. Not everyone goes off road for sheer excitement, to tear stuff up with a bunch of buddies on trail rides. I want to know what my vehicle does vs other options. I feel like its often a subject of taboo. As I said before, the old guys I hunt with throw mud tires, leave it stock, and roll thru some rough, muddy, steep terrain. Have we modded stuff before, SURE! My uncle rolled a CJ-5 with 38s down the mountain and it looked like a plane crash!! Haha. I had a 94 Yota, lifted, would straight up dig... we own those mountains! BUT It's more about leaving it stock and changing out tires for summer as winter now days for us.

So I have determined that when it comes to the 97 Jeep ZJ Laredo V8 vs 98-99 Land Cruiser vs a P38 Range Rover

97 ZJ has Quadra Trac limited slip in front and rear most likely uses the BDL splitting power to all 4 wheels

98-99 Land Cruiser has locked rear and open front. Meaning, it's a true 3x4, rears locked sends power to front wheel spinning, other front gets nothing.

P38 Range Rover is basically like the ZJ whereas it uses the ABS to send power to the wheel not spinning

priced ARB front lockers for my 99. Material + labor about $2500

http://youtu.be/_HOa0aRZYpw

video of differential tech data. This guy does vids on diffs and gearing from a engineering standpoint!!

 

[stonepa]

Here's all I know. Whether it's my old 4Runner, my FJ 60, or my bone stock 100 I can drive the back road (not the nice one from on Hurricane side) on a muddy day up to Gooseberry Mesa in Utah. If you find a hunting road worse than that you'll still make it in your 100.

With the right tires and the right driver you could probably get a Rav4 or Highlander 99% of the places most people go. Even loaded with guns, grub, and hunters.

 

[SmoothLC]

^^ Nice, Gooseberry Mesa is a great example.

 

[Jody Highroller]

Here's all I know. Whether it's my old 4Runner, my FJ 60, or my bone stock 100 I can drive the back road (not the nice one from on Hurricane side) on a muddy day up to Gooseberry Mesa in Utah. If you find a hunting road worse than that you'll still make it in your 100.

With the right tires and the right driver you could probably get a Rav4 or Highlander 99% of the places most people go. Even loaded with guns, grub, and hunters.

Ha! None of us will ever get a Rav4 or highlander up skyline mountain via smalligan steep November thru January, my friend

I'm starting to realize why 4x4 specs are more important to me than many others. I'm having to go up a place called Skyline and smalligan Steep, and others are riding places called "gooseberry" hahaha

 

[Muddy Bean]

I've just been reading this thread mostly cause it's interesting, but I'll say this: different trucks hone in on different applications. If I just wanted a rock solid 4x4 for extreme terrain and constant abuse, it's not going to be a 100 series. Guys here who chronically abuse their 100s are replacing stuff like steering racks etc. the truck is stinking heavy too. That doesn't help. My 1989 4wd Toyota pickup weighed 3500lbs give or take and I really really abused it. Big time. Super big time. And I never replaced anything except the brakes tires and clutch. It was so light I could bounce my way through, over, and up stuff my peers couldn't in their Cherokees because I was light and nimble. The cruiser was built for comfort, reliability, quiet ride, capability to get through some gnarly off road situations and do it with heated seats and in comfort. They are a perfect blend of off road capable, (more so than nearly all of the suv junk out there) comfort (some American trucks are pretty comfy) and reliable (definitely wins the war in this department). If you are doing chronically extreme stuff, go with a solid axle 80 Series, 4runner, etc. just my opinion ...though there are a few 100s here that are bashed hard and will probably prove me wrong but that's ok. I own one and id like to be proven wrong.

 

[Junglejack]

Just to sum up. The AWD system itself is unchanged from 98-99's and points forward and is exceptionally capable. ATRAC and the like were primarily developed as an on road safety not and not to augment off road capability. Now things like it have even been mandated by the government for all vehicles. While the 100 Series are not stellar rock crawlers, it is pretty crazy to me to use a 5500lb+ wagon in the first place.

Given the location, I agree that an LC is more than capable. I am somewhat surprised the OP purchased one given the gas mileage and so forth without going over this prior. Also, I would not lose too much sleep if a bud in an old GC and old RR that combined are probably worth $500 (it is not for nothing that 100's sell for what they do and I can buy an RR Classic with the change in my ashtray) and unless modded offer questionable advantages off road critiquing the 100.

 

[Jody Highroller]

a rock solid 4x4 for extreme terrain and constant abuse, it's not going to be a 100 series. ...The cruiser was built for comfort, reliability, quiet ride, capability to get through some gnarly off road situations and do it with heated seats and in comfort. ..though there are a few 100s here that are bashed hard and will probably prove me wrong but that's ok. I own one and id like to be proven wrong.

Agreed. This is why I've not taking it up skyline yet. The uncles old ZJ is already beat on. My TLC is my DD. I wanted to be sure what power i was getting to the ground to before we took mine up. I don't want to sling a rod, spinning with the accelerator to floor. A vehicle with lockers would barely spin a tire going up, It makes such a huge difference, open diffs is asking to be stranded in this place. The ZJ goes good some days, struggles on some Days. The quadra trac sending power to the wheels with traction makes it a proven off road vehicle IMO. Ive seen it with my own eyes, for anyone that is curious. I think my TLC will be ok, I just can't stand it that my front is open diff. I read up last night and the TLC ActiveTrac system on the 2000-2007 is more capable than the 98-99. I still love my cruiser, heated seats, leather, kush ride, and with a front locker could be a great package and. I'd prefer the 4.7 engine reliability over the FJ80 solid axle.

http://youtu.be/KxiVNfwMp7A

Euro land cruiser 120 series with Active trac on roller ramp test.

These guys do nearly endless vehicle makes on this test in other videos. This is a proven way to tell what your vehicle does. They've exposed a lot of vehicle makers who claim to have full time /Awd/ off road / limited slip/ etc..

 

[duggy]

I never really liked to be a keyboard racer and sit on the Internet to compare data just to show off to your buddies. In Texas we have all types of terrain from mud to rocks. You can have all the technology in the world and prove anything with these roller tests but the true aids you should possess is your knowledge from past experiences and also another truck in case you get into trouble. You reduce your chances of getting stranded indefinitely with a second truck. Recovery equipment such as straps, winches, come alongs, hi lifts are must haves if you are trail riding.

 

[jgray]

I'll take the stock 98-99 rear locker over ATRAC any day. Just put a locker up front and you will be triple locked with selectable locker controls front and rear and be done with it. You can do it cheaper than $2500 (prob $1500) if you aren't regearing and just adding the front locker. Get out and wheel the 100 for a weekend and I think you will find it is a lot more capable than you realize.

 

[codertimt]

IMO, you're giving the ZJ more technological credit than it deserves. Not saying you haven't seen a limited slip diff sending some torque over to a non-slipping tire, but a '97 Quadratrac isn't going to have any kind of electronic traction control...and a front limited slip on a Laredo is going to be a rare bird...traditional clutch pack front LS on full time 4WD is fairly rare on anything as they are not not transparent on pavement and adversely effect handling. Although the NV249 is apparently 80/20 rear/front biased in 4HI, so it's still within the realm of possibility. LS rear with V8 is fairly common.

So, not saying it's not a very capable rig, not saying it's more or less capable than your 100, but there is nothing magical going on. You put it on that roller test and it will sit there. With near 0 torque for the 16 year old clutch packs to transfer a portion of over to the other wheels...it's not going anywhere. Obviously it works pretty dang good in the real world...but that should just make you realize that while these roller tests show how effective the technology is in theory...real world application is completely different.

Anyway, I'm with the other guys, the only way you will find out if the 100 is capable of running whatever trail the ZJ has been down is to try...preferably with a buddy to avoid ruining a day with long self recovery...
So, could only find a few vids with a search of Skyline Alabama...

http://www.youtube.com/watch?feature=player_detailpage&v=KbeSidaBBkk#t=49

Is this the kind of terrain we're talking about? If so, that's some fairly technical stuff there that will probably prove to be somewhat challenging...

And not to kick you while you're feeling down about your rig, but make sure you search out front diff failure before applying judicious skinny pedal out in the middle of nowhere...