TrueTrac Limited Slip in the front?

[Waggoner5]

With an Aussie I could see the reasoning behind hubs, but with an LSD, why put front hubs on period? I don't see the point. The front output will be spinning regardless. It won't help or hurt whether the front is open or not. Buy the LS because it fits your budget, but I think the weight of the 80 will cause it to slip more than normal. It will still work in most offroad situations at least until things get nasty.

 

[pulse98]

Alka,

I may have missed it, but is your rear diff open?
Since my 80 is unlocked all around, if I had a TrueTrac in my garage, I would install it in the rear instead of the front.

ST,
Would you you have additional comments if his rear diff was open?

 

[lowtideride]

I have been on trail with them, (havnt used them myself) but spotted rigs with them... and this is what I have seen..


they work OK until the point when you REALLY need them...then is just like being OPEN.

 

[woody]

real world experience ( I know, theory is much more fun )

I ran a LS in the front my FJ40...worthless POS...while it was an Auburn and not a TrueTrac, I'd never waste $$ on one again for any type of offroad use where a tire may get in the air.

Ran a TrueTrac in the rear of a 1995 minitruck...relative to the lunchbox locker that was in there for a week, it was transparent...til you got an tire in the air. same worthlessness.

Yes, I know brake modulation and all that...still a worthless POS and not something I would waste my money on.

Limited slips are just that - limited. If they weren't limited, they'd call them lockers.

 

[sleeoffroad]

Read the application. A full time case will work adding lockout hubs Christo, a VC full time case won't, but he doesn't have one of those. He now has the advantage of a part time awd vehicle. Lock in the front hubs, he has a trutrac front. Lock the center diff, he has even more torque available to both front wheels.

Re-read again. It might be the third best thing to do, but sure as hell not the best thing. Granted, I skipped the part that he has a 91/92. Still others will as well. Recommending installing hubs should go with the disclaimer RE; the front diff. Remember newbies read this.

Yer kidding right? Comparing a solid front axle 4R to a 80?

I never said solid axle 4Runner. I said IFS.

Christo, the only difference is when a wheel is in the air. In all other scenarios (the other 90% of the time), you speak to a 20% traction advantage. Is it the BEST?

You said it is the best thing to do, and now some people have also posted from real world experience, not AWD theory, that it is not. So why recommend it when it does not work. That would depend on what you are doing with the truck. I don't consider a locking front the BEST at more than extreme rock crawling.
[/quote]

The recommendations of a Lockrite in the rear is much better, but his question was not about that. I consider locking the front the BEST in all cases where you need traction.

One of my passion is awd vehicle dynamics Christo.

Yes, but your experience is not rock crawling.

Locking a front axle is easy, and allows 100% torque to be supported by either wheel under slip. A LSD will allow 80% torque to be transfered under slip. Got yer wheels in the air alot, put in a locker. That's the minority, daily driver or offroad daily driver.

How much have you wheeled the 80? It is not just lifting tires where a locker is needed , I can assure you that.

The post #1 understands that he's seeking compromise. Put in locking hubs and a trutrac, certainly not a *useless* compromise.

Some migh disagree, but again, it is not the BEST as you stated.

My point is, it's a good one with a good following. It will work better than a open front diff, and with locking hubs, won't affect driveabilty at all. I might say this is all BS based on Kunz' post, as he should concentrate on adding a rear locker first, which I agree with absolutely as a first step.
ST

If money is an issue, why make people buy POS just to buy a real locker later. That is throwing money away.

 

[ShottsUZJ100]

You know....if this was a 100 vs 80 thread some might think I changed my forum name to SUMOTOY. Damn....is that how I write on those threads? I gotta re-think my posts.

Here......N74L is no biggie, IFS is not superior to SFA for wheeling, hmmm....what else? OH...80's aren't gutless.

 

[-Spike-]

I'll say it again: a limited slip diff is close to worthless for four wheeling. Also, without adding front hubs, makes the vehicle dangerous to drive. It can make the vehicle dangerous off-road also, with the hubs locked. It will make the vehicle handle differently, which means there may be situations where 'differently' means 'difficultly'. Put an auto locker in the rear if you need to save money, and if you still need traction you're going places that will require a front locker anyway, not limited slip. In my opinion, it's a waste of money for that reason.

-Spike

 

[SUMOTOY]

With an Aussie I could see the reasoning behind hubs, but with an LSD, why put front hubs on period? I don't see the point. The front output will be spinning regardless. It won't help or hurt whether the front is open or not. Buy the LS because it fits your budget, but I think the weight of the 80 will cause it to slip more than normal. It will still work in most offroad situations at least until things get nasty.

W5 I'd put the hubs on because when they are unlocked, you have no LSD function. LSD will only work if you have torque generation at the output shafts. If you lock the center diff and unlock the front axle, the front driveshaft spins, but there is not torque generated at the front wheels.

P98
I would put the rear locker in before I'd spend a dime on anything on the front

Christo:
I've done a lot of wheeling, rocks and otherwise. It's ok to say a locker is superior in extreme traction. An LSD is 80% of that, unless a wheel is in the air. Then it's at a disadvantage to a locker, but it's not useless, it's certainly better than open!

The 4R boys (including SFA) have used the LSD fronts with good success. I've ridden in one in extreme crawling, and I found it to be absolutely a great alternative to a locker front. YMMV. In less than extreme wheeling, I find it to be much more transparent in terms of feel and manners than a locked front is.

Is an LSD a compromise to all out traction? Ok. Is it better than open? Sure it is, and has a lot of handling benefits that can't be matched with any locker. And with lockout hubs, it's totally inactive when the hubs are locked out.

"The HMMVV, or Hummer, uses Torsen® limted slip differentials on the front and rear axles. The owner's manual for the Hummer proposes a novel solution to the problem of one wheel coming off the ground: Apply the brakes. By applying the brakes, torque is applied to the wheel that is in the air, and then five times that torque can go to the wheel with good traction."

Everyone shouldn't assume post #1 is going extreme crawling, he didn't even say he did rock crawling. And no one even asked? As such, the LSD is garbage is a bit over the top. Spike, offroad 'unsafe' because it handles differently? Assuming locked rear here with center diff locked, you have a lot of understeer already. If you make the claim that the front LSD is unsafe because it handles differently, then a locked front is worse by definition, because a locker allows no wheel speed differentiation in the front with torque applied to the steering wheels, an LSD allows wheel speed differentiation to the steering wheels with torque applied.

How 'bout A-trio post up more information. Like where he offroads, how he offroads, and what gains he's looking to get.

ST

 

[sleeoffroad]

Christo:
I've done a lot of wheeling, rocks and otherwise.

In the 80? That is what I asked. Not if you have driven with someone in a 4Runner.

Could you at least at some point acknowledge that it is not the best? Any time someone ask about a traction aid device, I assume they want extra traction. How many have posted that they pulled a full locker and installed a LSD, vs the other way round?

 

[DuManchu]

Picture yourself in a situation where you have to turn a corner quickly.

Now picture the front wheels locking 1/2 way through that turn.

Now picture your truck over steering, sliding, through an intersection, into the side of a car full of nuns.

Auto lockers on the front = real bad dream.

Auto-locker != Limited Slip

 

[lowtideride]

Auto-locker != Limited Slip

What the hell are you talking about?

 

[SUMOTOY]

In the 80? That is what I asked. Not if you have driven with someone in a 4Runner.

Many times. I have a couple extra flares because of it.

Could you at least at some point acknowledge that it is not the best? Any time someone ask about a traction aid device, I assume they want extra traction. How many have posted that they pulled a full locker and installed a LSD, vs the other way round?

Not the best for what? Post #1? Not enough information Christo! I assume adding LSD or lockers, folks want extra traction too! I don't assume this to mean rock crawling with a wheel in the air. If I was wheeling in GA, or the Northeast where trees are a big factor, than the maneuverability of the LSD would have the advantage, especially in the 80. The question isn't about pulling lockers, the question is about installing a traction aid device on an open front axle.

This forum does a lot of rock climbing, I venture because big footprint tanks aren't at a disadvantage there. I have done a lot of offroading where a locked front would be at a distinct disadvantage. Welcome to the midwest!

I assume when folks bring me their audis for track prep, they want extra performance. I don't assume they want me to buld them a race car. I see a lot of similarity here.

ST

 

[-Spike-]

Spike, offroad 'unsafe' because it handles differently? Assuming locked rear here with center diff locked, you have a lot of understeer already. If you make the claim that the front LSD is unsafe because it handles differently, then a locked front is worse by definition, because a locker allows no wheel speed differentiation in the front with torque applied to the steering wheels, an LSD allows wheel speed differentiation to the steering wheels with torque applied.

ST

I swear, you just like being difficult. The front LSD is unsafe because it CANNOT BE TURNED OFF. Unlike you, with all your fully locked Quattro experience, most people leave their lockers, and especially the front locker, OFF until it's required. I personally drive most trails with the center diff locked, and difficult trails with the rear locked, but I never drive with the front diff locked until it's needed. If I'm driving fast on gravel, neither axle is locked. That's not possible with an LSD without getting out and unlocking the hubs, and then you have no 4wd.

Your views on lockers would be humorous if I were talking to you face-to-face, but not so much when there are other people listening, thinking you might know what you're talking about. I know of several experienced people on this board who prefer not to get into these arguements with you anymore, and I wish I were one of them.

-Spike

 

[ShottsUZJ100]

I assume when folks bring me their audis for track prep, they want extra performance. I don't assume they want me to buld them a race car. I see a lot of similarity here.

ST

WHAT?

 

[DuManchu]

What the hell are you talking about?

The post I quoted sums it up, he's talking about an auto locker, not a limited slip. That's all.

"!=" is computer geek for "Is not equal to".

 

[lowtideride]

Many times. I have a couple extra flares because of it.




This forum does a lot of rock climbing, I venture because big footprint tanks aren't at a disadvantage there. I have done a lot of offroading where a locked front would be at a distinct disadvantage. Welcome to the midwest!



ST

Yes they are. Thats the major problem.

 

[sleeoffroad]

Not the best for what? Post #1? Not enough information Christo!

Re-read your post. You said Best. I never did. You used the same base information in post 1 and posted the following.

I disagree. In fact, it's one of the best mods for a locking hub front axle.

 

[lowtideride]

The post I quoted sums it up, he's talking about an auto locker, not a limited slip. That's all.

"!=" is computer geek for "Is not equal to".

gottcha

 

[SUMOTOY]

I swear, you just like being difficult. The front LSD is unsafe because it CANNOT BE TURNED OFF. Unlike you, with all your fully locked Quattro experience, most people leave their lockers, and especially the front locker, OFF until it's required. I personally drive most trails with the center diff locked, and difficult trails with the rear locked, but I never drive with the front diff locked until it's needed. If I'm driving fast on gravel, neither axle is locked. That's not possible with an LSD without getting out and unlocking the hubs, and then you have no 4wd.

Well, acutally a truetrac is the equivelent of a torsen, it is a torque sensing gear type limited slip differential. Therefore it can be installed without front locking hubs. And it distributes torque exactly like a locked diff up to it's TBR WHILE allowing wheel speed differentiation. It's always fully active in the front of a Hummer, don't see a lot of them having accidents!

Your views on lockers would be humorous if I were talking to you face-to-face, but not so much when there are other people listening, thinking you might know what you're talking about. I know of several experienced people on this board who prefer not to get into these arguements with you anymore, and I wish I were one of them.
-Spike

I find misunderstanding of differentials to be a big problem here. In vehicle dynamics, there are a lot of factors that dictate 'unsafe' and a lot of factors that would dictate the use of a given differential.

Since the production Hummer uses a torsen (trutrac equivelent), I see no reason why you couldn't in an 80. Up to it's TBR Spike it allocates torque EXACTLY like a locker. And it allows wheel speed differentiation exactly NOT like a locker.

I don't think I'm missing anything here. Anyone is welcome to come to my Steamboat Ice Event in February, and demonstrate to me their understandings of awd vehicle dynamics. I personally believe having 80%locking ability with a torque sensing gear type LSD at the front wheels while allowing wheel speed diferentiation has a lot of advantages over a locker.

YMMV

ST

 

[ShottsUZJ100]

Spike....let It Go!