By Brett Barton (Brett) on Thursday, December 06, 2001 - 09:11 am: Edit

My question is in regard to the Jeep Quadra-Drive system only. Not Quadra-Trac or Selec-Trac. Quadra-Drive is supposed to be able to transfer all power to one wheel if necessary. I am curious how this system works. I understand how it works technically. I have never wheeled with a Grand Cherokee that had Quadra-Drive and was wondering if any of you have? How did the Quadra-Drive system seem to work (tractive properties, problems, etc.)? I am wondering how this pits against a stock Disco with Center Diff Locked.

By Mike Rupp (Mike_Rupp) on Thursday, December 06, 2001 - 09:57 am: Edit

My wife has a Grand Cherokee with Quadra-Drive. I can tell you that on road it is great. In the rain where my Disco spins a tire, the Jeep takes off with no spinning. However, my wife will not let me take it off road. I'm interested to see what would happen if it lifts a tire off the ground.

By Brett Barton (Brett) on Thursday, December 06, 2001 - 10:06 am: Edit

I have an enormous amount of experince driving various Cherokee's and Grand Cherokees off the road. I think that they are wonderful vehicles. I have not had the opportunity to drive a Quadra-Drive though and that is why I posed the question above. I used to be an engineer for Chrysler so I always drove Jeeps. I love my Disco, but Jeeps are good vehicles as well. A good driver in a Grand Cherokee can take it well past an average driver in a Disco. I am anxious to see Quadra-Drive in action.

By cartner on Thursday, December 06, 2001 - 10:09 am: Edit

Yeah, but a good driver in a disco....

By PerroneFord on Thursday, December 06, 2001 - 10:20 am: Edit

The quadra-drive system is similar to the system that is installed in the Hummer. Basically it operates in rwd until the center diff (limited slip) detects a speed difference between the axles, then it shifts into 4wd. Each axle also has a limited slip in it

The Disco has a center diff that actually LOCKS which gives better performance off road, but since you have to use it unlocked on the road, it sacrifices some performance there by comparison. The Disco also has open diffs whereas the jeep has limited slips. They provide much more traction in slippery situations on and off road.

To be fair, the Jeep 4wd system is the better of the two by a wide margin. The disco can be modified to have most of the advantages of the jeep but that center diff lock that helps so much off-road is still somewhat limiting on-road comared to the Jeep. The Range Rover has a center diff much like the jeep except that it doesn't bias so much torque to the rear all the time. Unfortunately, it has open diffs just like the Disco.

There is a pretty nice description of the Jeep diffs here:

http://southafrica.jeep.com/english/gr-cherokee/4wd/feature2.html

-P

By AL on Thursday, December 06, 2001 - 11:22 am: Edit

I must disagree with Brett on offroading JEEP VS DISCO. I have both and have wheeled both hands down Disco wins.
Jeep can have the champion offroader driving it and ill drive my Disco, and help him get up the little hills. On the pavment the jeep moves like a speedster and can win on pavment. Fit and finish goes to the Disco. Reliability they both have issues.

By Milan on Thursday, December 06, 2001 - 12:06 pm: Edit

The system on the Jeep works better than traction control on the DiscoII. I'd also take the gerotors in the diffs over any open diffs. However, for the t-case, I prefer either part time systems or at least the lock option on the Disco. All you need then is either 2 TrueTracs or locker/TT combo in the diffs and you're better off. For "racing" GC off-the line in slippery conditions with the above combo, just lock the center diff and then release it as you get going. I still think you'll loose as the GC is peppier but who cares. It's a unibody, yuck! If I wanted that, I'd get an Audi A4 or A6.

By PerroneFord on Thursday, December 06, 2001 - 12:11 pm: Edit

Uh oh! Jeep vs. LR!

Al, you stateed that the Disco wins hands down off-road. Now I have not driven a JGC or anything with the Quadra-Drive, so I am really curious. Do you feel that the center diff lock on the Disco with 2 open diffs gives it superior traction to the Jeep with limited slips front center and rear? Is the disco winning in your terrain becaue it flexes better? Tires are better?

What type of terrain have you wheeled both of these in? I'm not familiar with where you are from so I am just wondering where the Disco does so much better. For the purposes of this discussion, I am not worried about fit/finish or build, just 4wd capability...

Thanks,

-P

By Jon Williams (Jonw) on Thursday, December 06, 2001 - 12:25 pm: Edit

Well Brett, that doesn't say much for the Jeep. Hell, a good driver in a Plymouth Valiant can go further than "an average driver in a Disco" can...

Nonetheless, Quadra-Drive (or whatever it's called) is an impressive system.

By p m on Thursday, December 06, 2001 - 12:29 pm: Edit

FWIW - here's my humble opinion:

the jeep's Quadra-drive system is the best 4wd set-up, hands down. Think of a lockable limited slip center diff (a combination of LT230 and range rover's BW case), and two true-tracs in the axles. In fact, the jeep's diffs are better than true-tracs - they are nearly open when there's little wheelspin, making them safer to drive in icy/rainy/snowy conditions. And they lock up progressively as the wheelspin increases.

i've seen a JGC with a QD system off road, and it was very impressive. it would outdo an open-ended disco 1 traction-wise, believe me.

to put out potential fires, the entire vehicle (JGC) is less suited for off-road driving - weaker axles, very soft unibody, relatively high center of gravity, etc. etc. Also, mechanically, QD's diffs are more complicated, and thus potentially less reliable than truetracs.
But, as far as the entire 4wd setup goes, there's no competitors.

just in case, Perrone, it has CDL, and it is a permanent 4wd setup just like any land rover, so act accordingly.

Brett - i have an old QuadraTrac jeep, and like it a lot. Why couldn't they make a center diff lockable in the RR's borg warner t-case?...

peter

By PerroneFord on Thursday, December 06, 2001 - 12:49 pm: Edit

So, it has a limited slip CDL AND you can lock it? Now that's a neat setup! I sure wish the RR had that. I wonder if BorgWarner ever tried to market a setup like that? I couldn't imagine LR wouldn't buy them if they did. Seems like the best of both worlds.

-P

By Mike wht d1 on Thursday, December 06, 2001 - 12:54 pm: Edit

Last Sunday about 4 cherokee's modified with lifts and suspensions tried to follow our Disco's around Hollister Hills for a while and couldn't hang with us Big Dogs. I have a completly stock Disco and those jeeps were unable to go up or down the same hills I went on in the mud

By PerroneFord on Thursday, December 06, 2001 - 01:01 pm: Edit

Which of the 4wd systems did they have? I don't know why, but Jeep only seems to offer the really GOOD one on their best truck, and even then, its an option. Well at least it was that way a couple years ago when I priced them. Maybe its different now. Were these new trucks?

-P

By Ali on Thursday, December 06, 2001 - 01:14 pm: Edit

Hey Brett,

Got a question for you. I'm helping a friend find an used Cherokee so we test drove a '92 and '93. The vehicles had two selections of 4wd of particular interest to me: 4wd part and 4wd full. When we engaged teh 4wd part time and made turns, the front wheels hopped around on dry pavement but on 4wd full time everything was silk smooth. What're your thoughts on this? Email me off list if you don't mind discussing this further and other things we should be aware of!

Thanks.

By Milan on Thursday, December 06, 2001 - 01:15 pm: Edit

peter,
I think the TT's are almost as good as the gerotors in terms of progressive lockup. I.e. they also act as an open diff until slip is detected. Where the gerotors win is when they actually lock up automatically when one wheel leaves the ground or slips a lot. For the TT to lock up you have to fiddle with the breaks to distribute the torque. I still like them better as they are simpler and should have no wear issues. The GR have clutches that wear. But it is a very impressive system in any case.

Perrone,
I also like the stories about how this vehicle or that can't follow that one or the other. I bet if the same driver were to wheel them both, they'd do similarily. I have seen both cases of Jeep not being able to follow a LR and vice versa. It boiled down to the setup (one being better than the other for specific obstacle) and the driver in all cases.

By Milan on Thursday, December 06, 2001 - 01:17 pm: Edit

Ali,
The part time system is like engaging the center diff lock in your Disco. The full time let's you drive both diffs with some differentiation between them. So, what you experienced was normal.

By PerroneFord on Thursday, December 06, 2001 - 01:21 pm: Edit

Well, I wasn't trying to be funny. The Jeep people have 3 or 4 different 4wd setups and I would have to guess they are all differently capable.

I just have a hard time imagining that a vehicle with the near the equivalent of 3 lockers couldn't follow a stock disco. I like my LR and all, but come on...

That's why I was trying to see which 4wd system might have been in these jeeps. I could easily see how a Disco with open diffs might best a jeep with open diffs.

-P

By Jack on Thursday, December 06, 2001 - 01:25 pm: Edit

1 - Do other autotrannys like the JGC have engine breaking for going down hills or do they have to ride the breaks?

2 - When driving a standard manual shift tranny how do you stop it from rolling back when your attempt at the hill climb fails ?

By PerroneFord on Thursday, December 06, 2001 - 01:28 pm: Edit

Jack, I think engine braking is more a matter of gearing. The EFFECTIVE gearing of an auto tranny is somewhat less than a manual with the same gears because it slips, but if you put 4.7s in a Range Rover, it'll creep downhill just fine.

#2 is an interesting question. I'm looking forward to those answers. I don't get to see too many failed hill climbs here in Florida!

-P

By Clint on Thursday, December 06, 2001 - 01:47 pm: Edit

Jack
You stop the same as normal. Jam the clutch and brakes.
Select reverse and back down very carfully using the brake to slow you if engine braking isn't enough...no big deal.

By p m on Thursday, December 06, 2001 - 01:51 pm: Edit

Perrone -
i have a 79 jeep cherokee with a full-time 4wd borg warner transfer case that has viscous coupler on a center diff, and a CDL. Jeep had this case from 73 to 79, called Quadratrac, on CJ7, Wagoneers, and Cherokees, behind a 304/360/401 cid V8 and TH400 transmission. i suspect the bolt pattern is the same or close, and outputs are on the passenger side, but jeep's case has 2.72:1 low range, worse than the range rover. I guess the reason for it was the gobs of low end torque from AMC v8s.

Milan -
truetrac is tight enough for you to notice on the highway, and thus it may send you into a spin on a slippery surface. The QD diffs are "more open" than truetracs in normal operation (like, progressive engagement vs. linear like TT).

Jack -
you use your brakes, then shift into reverse and back down the hill. that's in theory. in practice, a failed hillclimb... i hate them.... i liked the autobox because i could back down having the transmission in the 1st, and modulating the speed of descent by a feather-light application of throttle.

peter

By Discosaurus (Discosaurus) on Thursday, December 06, 2001 - 02:36 pm: Edit

Failed climbs are always fun with a gearbox ! One always needs at least one more foot at the start. I think my daughter has heard most of her 13 years worth of cuss words while I was recovering from failed climbs.

hehe

keith
discosaurus

By p m on Thursday, December 06, 2001 - 02:50 pm: Edit

good thing you live on relatively flat land, Keith

peter

By Jon Williams (Jonw) on Thursday, December 06, 2001 - 03:26 pm: Edit

A few years ago I was teaching my son off-road driving in my Disco (automatic) and he was able to stall it on a failed climb.

...that was before he realised the necessity of putting it in reverse on the way down

By p m on Thursday, December 06, 2001 - 03:44 pm: Edit

WOW... how did he do it?

with an automatic, it is not a necessity to put it into reverse on the way down. it is an option for not very steep hils.

peter

By Discosaurus (Discosaurus) on Thursday, December 06, 2001 - 03:52 pm: Edit

good thing you live on relatively flat land, Keith

I think that every time I'm wheeling out west.
Big hills and big rocks always make me re-think my love for gearboxes.

By p m on Thursday, December 06, 2001 - 03:54 pm: Edit

isn't that sad?

i love stick shifts, and all my 4x4s are automatics (and i don't have any other vehicles)

btw, what's the typical lifetime of a disco clutch?

peter

By Discosaurus (Discosaurus) on Thursday, December 06, 2001 - 04:20 pm: Edit

Probably around 100K if you offroad frequently - 150K on the road.

I've been told I'm easy on clutches. I had an ALFA that wore out it's throwout bearing at 200K well before it had any lining issues. Italian clutches are notoriously easy to fry.

By p m on Thursday, December 06, 2001 - 05:17 pm: Edit

don't tell me.... i drove a russian clone of a fiat 124 for years...

peter

By Kingfish (Kingfish) on Thursday, December 06, 2001 - 06:09 pm: Edit

I'm an engineer and I used to do a lot of remote field work. I drove a Cherokee, 4L, at my last job for about 4 or 5 years and I can surely say it was a very fast vehicle (as 4x4's go). I drove it through deep mud, and heavy rain a few times. I bottomed out once in a farm field and had to dig it out with another guy I was with (that was pre-cell phone days) Another time I almost slid off a dyke and into dredge waste after a heavy rain. It also scared the hell out of me driving on the highway in the rain. It wasn't anywhere as good as the Disco.

By Milan on Thursday, December 06, 2001 - 06:12 pm: Edit

So peter,
Was that a Lada or Ziguli, hehehehe.

I like stick especially with the hills we do out west here. I do stall and I do screw up but at least I know I'm the one to blame. And I just love the stick on the way down.

By p m on Thursday, December 06, 2001 - 06:42 pm: Edit

they are called zhiguli in russia and lada - in the rest of the world (that sees them, that is )



peter

By Milan on Thursday, December 06, 2001 - 06:51 pm: Edit

I thought they had to call them Zhiguli because they got sued by Lada (sewing machine company) for unauthorized use of the trademarked name. Anyway, pretty cool car but I like my Disco better. I drove one in Yugoslavia with a 1200cc engine and it was quite peppy...........compared to 1000cc Skoda. Hehehehe

By D Cantrell (Discodad) on Thursday, December 06, 2001 - 07:29 pm: Edit

OK so Back to the Jeep verses Disco.
I had a sticker on the back of my 88 RR
" I rather have my Rover towed than ride in a JEEP"
Not sounding like an elitist snob, I have owned all the popular 4X4. The best I ever had towed was my Rangie.

DiscoDad

By p m on Thursday, December 06, 2001 - 07:54 pm: Edit

Milan -
naw, they were always called zhiguli. apparently, in some country that was targeted for export, this word sounded like some obscenity, and hence lada name came up.

Dee - it wasn't jeep vs. disco, it was (i guess) whether quadra-drive setup was any good. i've seen one in action and was impressed (by the 4wd work, not by the JGC as a vehicle).

now, do you want your disco towed? we can go to Bronco Peak or Los Coyotes! i haven't even been to johnson valley...

peter

By William Turner (Wturner) on Thursday, December 06, 2001 - 07:58 pm: Edit

I have the shirt "I'd rather push a Land Rover than drive a Jeep"

Truth be told I think I would rather drive a the jeep, but I haven't had to push my Rover yet, so I am happier with it.

I have a friend that has a 2000 or 2001 JGC, 2wd, but everything else is as good as it gets. He only has about 20,000 miles on it, but we are young college kids so they are HARD miles. I joke that his car only has two options, either gas pedal to the FLOOR, or Brake pedal to the FLOOR. Anyway, as I said it is a 2000 at least, and it takes him twice to start it at times and is very slugish in the cold. I drive mine just as hard with 60,000 miles and it runs like a CHAMP even in the cold!!

No one has ever gotten into his car and been overly impreased, and no one has ever gotten into my 1997 Disco SE, and NOT been overly impreased. I have a friend who just got a 1994 LWB Rangie, and that back seat is SOOOO big, you know we all love that.

The two sunroofs killes em every time (in mine, not the rangie of cource), then I show them how to open it, and they are SOLD. All my friends love "the Rover truck".

I will stick with the stunning impact anyday.

By p m on Thursday, December 06, 2001 - 08:19 pm: Edit

hehehe

"stunning impact" applies also to collision accidents

peter

By ZPukajlo on Thursday, December 06, 2001 - 08:23 pm: Edit

How does the Quadra-Drive compare to the RR's system? Which, in your opinions, is the better of the two?

Z

By PerroneFord on Thursday, December 06, 2001 - 08:40 pm: Edit

The Quadra Drive has to be superior. The RR has open diffs just like the Disco.

By p m on Thursday, December 06, 2001 - 08:44 pm: Edit

unfortunately...

peter

By D Cantrell (Discodad) on Friday, December 07, 2001 - 12:27 am: Edit

PM,
Let me transform the Disco a bit more, I need some recovery and Safety upgrades. Ill look forward to hitting the trails with you soon.

I do have to say my Jeep Cherokee did rather well in the crash test department. While pulling a small trailer the left rear tire fell off at 3 am outside of Phoenix, not much damage but a nasty rear brake and drum. The seats were also stain resistant.
I did like the Quadra track? I think thats what it had 1994 model? and the 4.0 6 cyl; I never got stuck in it. The HP to weight was much better than the RR or the Disco. Peter you have a “Real Jeep” with a proven off road legacy not the soccer Mom specials offered up today.

Every one I know that owns a Cherokee is trading it in for the new Toyota. They were not impressed with SD LR Dealer. I tried to convert them.

My only complaint about the Disco is the 4.0 Liter give me some more liters 6.0.
I like that Monster Motor RPI has, give me about 75K more on this one Chris and ill look you up.
D

By Brett Barton (Brett) on Friday, December 07, 2001 - 08:07 am: Edit

Guys, the Quadra-Drive that I talked about initially in this conversation is only available on the Grand Cherokee starting in 2000. It is not available in any other Jeep product. I guess a lot of these Jeeps are still too new and their owners are not taking them to the point that we can see if Quadra-Drive is really a good set up or not. I also want to see how they hold up to mileage.

By ZPukajlo on Friday, December 07, 2001 - 09:16 am: Edit

Hey Peronne,

I was reading the RR threads and came away with the assumption that a Rangie has a much better system than other LR's. If this is true than it should be the equivalent to the Jeep's Quadra-Drive right? Open diffs shouldn't make much of a difference.

Z

By PerroneFord on Friday, December 07, 2001 - 09:23 am: Edit

Incorrect, at least for the RRC (pre-1995). The RRC has the same axles as the disco. The CDL on the RR is actually a viscous only unit, which has some advantages on the street, but the Disco system is superior off the road.

The newer RRs have the same system as the DiscoII. This is indeed superior to the Disco 1 and the RRC. But I'd take a set of lockers and a lockable CDL anyday.

And open diffs make a HUGE difference, ALWAYS.


-P

By ZPukajlo on Friday, December 07, 2001 - 09:44 am: Edit

Doesn't the RR have a Center locking differential where the DII doesn't? Add that to ETC and it should be a great system. You're right about open diffs. I meant to say that under this system it shouldn't make much difference. Where a stock D1 would get stuck the Rangie should breeze on through right?

Z

By PerroneFord on Friday, December 07, 2001 - 10:09 am: Edit

Again, the Rangie had a locking center diff until about 1988, and from then on, it has been viscous. IT DOES NOT LOCK. The DI center diff setup is superior off-road.

ETC does add some advantage over a D1, but DIIs also have ETC. And I don't care what the marketing books say, ETC is a poor substitute for lockers.

As for breezing through, I think not. ETC helps, but if you've ever seen ETC in action against a vehicle with open diffs, you'll know that it is not breezing through anything. It may get you where the open diff truck gets stuck, but it is anything but easy. I'll STILL take the lockers anyday of the week.

By Ron on Friday, December 07, 2001 - 10:52 am: Edit

The NBS RR ETC (especially after mid 1999 when they went to four wheel ETC) is superior to the DII ETC and it has the VCU center dif.

By PerroneFord on Friday, December 07, 2001 - 10:54 am: Edit

Ron,

Is the DII ETC 2 wheel only? I thought they were going to install 4WETC?? Do you know if the HDC acts on 2 or 4 wheels? Someone asked me that, and I had no answer.

-P

By Ron on Friday, December 07, 2001 - 11:24 am: Edit

The DII is 4Wheel ETC.

The difference is that on a Newer NBS RR it kicks in sooner and is set up to know about the VCU where as on a DII it still trys to cross brake. Earlier NBS RRs (and 93-95 classics) have rear wheel ETC.

HDC works on all four wheels.

DII ETC is marginal for ETC. Too many RPMs to kick in (IMHO) NBS ETC is phenominal. Really good. Not dual ARB good, but close to dual TT good.

Ron

By PerroneFord on Friday, December 07, 2001 - 11:33 am: Edit

Here's my thing..

What do you think it cost LR to develop and install the NBS ETC system? What do you think it would cost them to install dual TT? This is where BMW/LR drops the ball for me. If the $500 solution is good, the $5k solution must be better.

-P

By Ron on Friday, December 07, 2001 - 11:41 am: Edit

P,

I think it is cheaper to have ETC. All ETC is is a computer chip that tells the ABS what to do. If you have ABS already ETC is (for a car manufaturer anyway) just a reprogramming of the computer.

TTs make noise and effect handling. No matter how slight this is, the majority of NBS RR owners would not like it.

My 2 cents

Ron

By Milan on Friday, December 07, 2001 - 11:56 am: Edit

Ron,
if your TT makes noise, there's something wrong with it. What noise are you talking about? Is this specific to TTs on LRs?

The handling is a very personal thing. I find I can't tell on pavement that it's there at all and in the winter it beats open diffs.

If there ever were 5 products that I really liked they are TTs, GY MT/R tires, Atlas II 4.3 t-case, Warn 8274 winch, and Wilson Trucker 2000 CB antenna. I'm sure there are other good products or better ones in some cases for particular applications of for somone with different tastes but these are gerat performing all-arounders. If I were a 4x4 manufacturer/dealer I'd stick the TTs in every vehicle I sell.

By ZPukajlo on Friday, December 07, 2001 - 11:59 am: Edit

Ron,

Do you think the RR system compares well with the Jeep's Quadra-Drive?

Z

By Ron on Friday, December 07, 2001 - 12:19 pm: Edit

TT makes noise when it engages.

I think it is normal and that is what I am told so I don't worry.

I think the NBS RR system is at least comparable to the J**p system but I have not seen a quarda drive in person on a trail so that is only conjecture.

Ron

By p m on Friday, December 07, 2001 - 12:22 pm: Edit

Ron,

TT is quiet as a computer mouse. if it makes noise, it is a goner.

Z -
RR's system is electronic, assisted with a viscous coupler in the center diff (open axle diffs). Jeep's QuadraDrive is all mechanical, with lockable center diff (progressive limited slip axle diffs). To say which is better is a matter of personal preferences. My vote goes for mechanical.

Perrone -
it is fairly obvious why LR doesn't put TTs in the trucks, it is a potential liability. Would you expect an average soccer mom consciously drive 15 mph slower than the open-diff'ed traffic on ice? This is exactly the same reason why Jeep never put any traction diffs in full-time 4WD QuadraTrac jeeps (back in the 70s). And this is yet another advantage of new QD set-up - when there's very little difference in the wheels' rotation rate, the diffs are nearly "open."

peter

By Ron on Friday, December 07, 2001 - 12:29 pm: Edit

So you are telling me that you can't hear anything when you lift a wheel and the worm gears kick in or whatever? It is not loud but I hear something.

Wait, now let me think. Am I hearing the ABS pump as I slam on the brakes or am I hearing the TT.

I am forgetting I heard anything. please carry on.

Ron

By Milan on Friday, December 07, 2001 - 12:31 pm: Edit

peter,
I know where you're coming from but the statement about having to drive 15mph slower than with open diffs on ice does not make sense to me. People are affraid of traction diffs on ice. I find them better than open diff because they don't slip as easily. It is true that if you punch the gas, the rear will go sideways but normally it is wheelspin that causes the slide and the open diff will slip sooner than LSDs. That's why I don't buy that liability shit but it's probably true. I think the society should focus more on educating people and driving would fall in that category. If there's one place I think the TTs shine it's in slippery winter road conditions, especially if you have f&r axles engaged and on the Disco you would.

By p m on Friday, December 07, 2001 - 12:38 pm: Edit

Milan,

we live in the area that hasn't seen a drop of rain in 159 days this year (san diego, that is). Whenever rain hits, cars end up upside down because people used to take all these highway curves at 20mph above speed limit, and it takes them too long to adjust their habits.

now, every winter, we go skiing and off-roading to the mountains (and so seems to do the entire population of LA/Orange County/SD). Imagine a highway with an official speed limit of 55mph, but with yellow warning signs in the turns saying 15? Cover it up with some slush or ice, and you get the picture. Most turns are either flat, or with a wrong slope to them.
Even a single TT makes a difference, which i found at Mammoth on the turkey weekend. Step on it a bit too much, and you're sideways. TT does shine all right, but when you need to take off, not when you're already going.

peter

By Milan on Friday, December 07, 2001 - 12:52 pm: Edit

Peter,
Like I said I know ehere you're coming from, so I'm not really arguing. We get snow and ice every year, yet every year the frist snow hits and we get in excess of 140 accidents (sometime over 240) in a single day. Makes you wonder.

I do however disagree on the TT only being good for take off. I found that rear only TT and open front would push through corners more than open rear or light LSD rear (trak-loc) and open front. Give it gas with rear only TT and it would spin around easier. True. With TT f&r and the front disengaged (on a Heep) it would push even more than with open diff up front. BUT engage both (which would be the case on a Disco) and the TT's actually pulled the vehicle through the same corner (yes I used several very familiar corners to test this) better and with less slip. So for rear only application I'll agree with you but for f&r I really think the TT's are actually safer both off the line and while going.

But id does not change the fact that it's the monkey behind the wheel that has to know how the vehicle behaves.

By p m on Friday, December 07, 2001 - 12:57 pm: Edit

can't argue with that - need a front TT. will be there soon

i would imagine having both TTs in a disco would make it slide outside the turn, but remaining parallel to the median (not front or tail out). I could live with that.

btw, whenever my wife complains about sloppy steering, i tell her - use your right pedal! the rear TT really helps to settle it.

peter

By D Cantrell (Discodad) on Friday, December 07, 2001 - 02:28 pm: Edit

PM,
You have TT on the front and DT on the rear, ?
How does this suck up the performance, and gas Milage? and does this also affect tire life?

Also stand out on 8 east and slosh a bucket of water on the road, It will look like a scene from Smokey and the Bandit. Never mid getting those bone heads up around Big Bear on the first snow.

By p m on Friday, December 07, 2001 - 02:41 pm: Edit

no, i only have a TT in the rear. I will have one in front, too, but no plans for a Detroit yet. at least, not on a vehicle that's not my daily driver.

i have a clunky EZ locker in the jeep's rear, the BANG BANG BANG type.

neither seems to affect tire life or gas mileage noticeably. performance - a TT in the rear turned out a nice fix for a poor handling after the lift.

peter

By Milan on Friday, December 07, 2001 - 04:13 pm: Edit

Ron,

"So you are telling me that you can't hear anything when you lift a wheel and the worm gears kick in or whatever? It is not loud but I hear something."

I thought you meant while driving. However, when I lift a wheel in the garage, that wheel spins with regular gear noise no clunks as far as I can tell. This is because the worms should not jam against the case and the diff should act "open" at this point. Maybe you hear their 'backlash' or general play in all the gears. Yes? No? Maybe? What do you think?

"Wait, now let me think. Am I hearing the ABS pump as I slam on the brakes or am I hearing the TT."

You should not be hearing the TT. Simple way to tell would be to disconnect the ABS and then do your braking test.

"I am forgetting I heard anything. please carry on."

OK. Either you're confused or I am. ????


Peter,
I was actually surprised to feel the vehicle push less through the corners, so you should not slide outside the turn but actually hold the line better. Now the trick will be the right application of throttle. You should find it works better if you actually are under power than when just coasting through the corner. If you coast you may feel a little pushing. I know it does not make sense and it surprised me too but once you get it, try it and let me know if your experience is the same.

Also, if you give too much throttle and break the front wheels loose, you will definitely push and depending on conditions it could be more or less than with an open diff but generally less - because both wheels are pulling in the direction they're pointed at. This is where the monkey comes into play.

Milan

Ron

By p m on Friday, December 07, 2001 - 04:45 pm: Edit

well, in the turns, i found that if i give it more throttle, it will try to track straight (doh), and thus take up all the slop in the steering.

on the straights, the same feature helped battle the wind-induced sway.

i was surprised to feel the TT at all on the dry pavement, but so far the feeling is only positive.

peter

By D Cantrell (Discodad) on Friday, December 07, 2001 - 05:54 pm: Edit

PM,
HO and Lee both have recommended the TT up front and DT in the rear. Sounds like a plan to me

Ill have to mow some lawns and setup my own car wash but I should be able to go with that setup providing I don't have to Pay to much to the IRS this year. Lets see I work until April to pay taxes then until May to afford the Disco hum.

How does this fit into the current discussion? I don't know but time to blaspheme, Jeeps are the Best 4X4 By far just ask Peterson Publishing. Oh Oh new topic coming on LRM vs. Four Wheeler Magazine

By p m on Friday, December 07, 2001 - 07:54 pm: Edit

LOL Dee,

ask Ho and John if they have any front OME HD springs

i will get a TT from EE a bit later, but, hopefully before i find out that i owe a small fortune to Uncle Sam.

Petersen Publishing? sure. they already said that the liberty's the best jeep ever built. once there was one guy - Rick Pewe - as editor of Jp, and you could see some occasional jeep truck once in a while, but no more.

peter

By ho on Friday, December 07, 2001 - 08:14 pm: Edit

LOL
oh yeah, we got plenty 751s. LOL
thanks to cheap bastard ron.

By p m on Friday, December 07, 2001 - 08:33 pm: Edit

he should have said it sooner... i could have bought four less 751s...

you guys need any more 751s? also, i have disco OEM rears!

peter

By Mud Man (Clarance) on Friday, December 07, 2001 - 09:14 pm: Edit

Out of the box, the disco wins hands down. Offroad ability is a primary focus of all LRs. But you have to love the pwr/wght ratio of a GC.

By D Cantrell (Discodad) on Friday, December 07, 2001 - 09:24 pm: Edit

Bring on the Cubes so far only a 5.2 is out I am waiting on a 6.0. Yeah Baby

By Milan on Friday, December 07, 2001 - 09:29 pm: Edit

Hey, Clarance, the gerotor system is out of the box. I did not see LR come with as much as a limited slip diff yet. I also don't see the GEMS systems as much of an off-road focus. Quite the opposite. But you're right. I'd take the Disco over GC no matter what they put in the diffs.

By Craig on Friday, December 07, 2001 - 09:43 pm: Edit

How about a DII w/ difflock engaged vs. Quadra-drive GC showdown? That would be a more fair comparison. Yeah, yeah I know the CDL isn't stock, but at least the driveline would be taken out of the equation.
Craig

By George Collins (Zinhead) on Friday, December 07, 2001 - 10:24 pm: Edit

If you read www.jeepsunlimited.com, you would find out that there is alot of variability in how the georotor equipped diffs engaged. Some dude posted that neither his front or rear georotor equipped diffs engaged when he got stuck. Others posted that thier georotors were tight and kicked in at initial wheelspin. Although the quadra-trac systems seems nice on paper, Jeep's manufacturing tolerances seem to leave alot to be desired.

As to the long term reliability of the georotor, I used to have a Bronco with a limited slip diff. Within 40K miles including alot of fire road use, the clutches in the rear diff had worn through and the Track-lock diff was effectively an open diff. At least with the LR ETC system, you would know when the thing works and when it doesn't. Unfortunately, with Jeeps system, you only find out it doesn't work when you get stuck.

By Ho Chung (Ho) on Friday, December 07, 2001 - 11:58 pm: Edit

aside from all the technical talk...
drive a disco, then go drive a JCG... the love just ain't there.

By Milan on Saturday, December 08, 2001 - 12:57 am: Edit

George,
The trac-lok is one of the weakest LSD's and the clutches don't last long. My Bronco one is shot and my Jeep one did not last more than 20K. It still worked after that but not as well when new but better than an open diff. However, they are very cheap to rebuild.

By Milan on Saturday, December 08, 2001 - 12:58 am: Edit

Oh yeah, Ho...I think you got it. I think more people should try it that way.

By Ho Chung (Ho) on Saturday, December 08, 2001 - 11:24 am: Edit

hehe, i bought the disco after test driving them both. and it was simply a no brainer.

By Milan on Saturday, December 08, 2001 - 11:38 am: Edit

I just wouldn't buy anything without a real frame. We were looking at another TJ (no defenders available) but we needed something with 4 doors for easier access to child seats. I sure as hell don't mind the comfort. My wife loves the GC and after we test-drove the Disco was way better than the GC. Myabe I brain-washed her but like I said neither of us are complaining. Hehehehe

By Ron on Saturday, December 08, 2001 - 11:54 pm: Edit

I dunno.

I hear it I am sure. Different than open.

I am not worring what I am saying. if it goes boom it goes boom.

Bill has not had one returned yet so I am going based on that as it is a tough dif.

ron

By Milan on Sunday, December 09, 2001 - 11:32 am: Edit

Ron,
they're pretty tough but not unbreakable. We busted 2 in the rear Dana 35. One due to the axleshaft breaking and the snap busted the worm gear. It was repairable in our opinion. All it needed were new worms. But it had to be send to Tractech and we have not heard anything in 6 months yet. The other got chewed up when the ring and pinion went and that went due to misaligned carrier (defective housing). It was replaced under warranty by the shop that did the install and then the second r&p set went but we think the TT is still OK we have not opened it yet.

I've run mine with 32", then 33" and now with 35" tires. I can't say anything if it breaks as it's only warrantied to 32" max. But so far it's holding up (fingers crossed). If it does break, I'll put a spool in the rear and if the front breaks, I'll replace it with same or Ox Locker or hopefully by then the ElecTrac will be out.

Did you check the diff? Any metal in the fluid. Few minute shavings are normal.

By Jon on Saturday, December 15, 2001 - 08:40 pm: Edit

Hey all,

Just thought I'd add some info on the Quadra-Drive system. I'm one of the lucky ones that has QD that actually works correctly. And, it's pretty impressive for a stock system. It's great for rainy weather, and it works pretty good for froading... haven't tried it much in snow or ice.

BTW, the transfer case on the QD system does lock, but only in low range. Also, this system was available starting in '99, the 1st model year for the new Grand Cherokee (WJ). Some people try to stay away from those 1st year Jeeps... some had many problems. My '00 has been great.

Jon

By Jeep Bigot on Saturday, December 15, 2001 - 08:42 pm: Edit

If the LR ETC is so vastly superior, how do you explain this?

http://jay.franklins.net/bin/sandyslope.mpg

(hee hee)

Seriously, though, as a Grand Cherokee owner, I am also a big fan of Land Rovers. I happen to think that comparing bone stock vehicles, the Land Rover is better offroad... for many reasons. However, QuadraDrive is certainly more suited to hardcore 4wheeling than ETC. QuadraDrive does not rely on the brakes, which can get wet, overheated, covered with mud, etc. Yes, it is true that it needs to be primed. When it does fail, it is usually in a situation in which Land Rover's ETC would fail too. The silver WJ in the above clip is mine, and I often wheel with that RR, which is a loaded '97 RR HSE. I have noticed that in some situations, the ETC is better. In others, the QuadraDrive is better. The ETC is often quicker to respond that the QuadraDrive... however, it gives up more easily.

And concerning mods.... The price difference between a loaded WJ and a loaded Disco II, is about the cost of a custom 6" lift, plus nice meaty 33" tyres. Or a supercharger.

Oh, and the next Range Rover to be released the end of next year will not have a frame, it will be unibody, and it will have fully independent suspension, front and rear. At that point, it will be about as good offroad as a Subaru or a Volvo.

And the next Disco? Too bad it is going to be sharing a platform with the IFS/IRS ford exploder.... hahahahaha