Is there a difference between a Limited Slip Differential and a Locker? I understand them to achieve the same thing. Deliver equal power to both wheels on an axle. Are they two different names for the same thing? Are they two different things that accomplish the same thing? Something else?
Is it possible that I have either? If not, how would I "add" it? Costs?
A "limited slip" differential will hold up to a certain point, where the force trying to make the coupling slip exceeds the limit of the differential's ability to remain locked. When this lets go, you have the equivalent of an open differential, which has no "traction control" characteristics, and so then you are dead in the water, exactly when you most need traction. The symptom is diagonally opposite wheels spinning.
The upside is that this device limits total stresses on the driveline and thus avoids breakage.
A locking differential, on the other hand, is just what it says. Like you'd welded together the internals.
An open differential means you can spin one wheel on one axle, if you're in 2wd or in 4wd with a slipping center differential.
Stock Pathfinders may have either a limited slip or open rear differential. How to determine this can be found by searching this forum. Stock Pathfinders have a lockable center differential, except for some fancier newer ones with the All-Mode system, which amounts to a limited slip/lockable center differential.
You can put a locking rear differential on your Pathfinder, IF it already has a non-limited slip rear differential. I've heard there are limited slip/lockable differentials made now, but I don't know if there's one that will work on Pathfinders.
Cost, I dunno. Besides this forum, you might want to post this question on www.nissan4wheelers.com, where some intense "modders" hang out. Don't forget the issue of increasing stress on driveline components, but people do make these conversions on Pathfinders.
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'91 Pathfinder SE 5spd (now sold)
'06 Suzuki Grand Vitara JLX-L
A "limited slip" differential will hold up to a certain point, where the force trying to make the coupling slip exceeds the limit of the differential's ability to remain locked. When this lets go, you have the equivalent of an open differential, which has no "traction control"
Thats not 100% accurate. Locker=Locked, It ussually will only work at low speed unless you disable the Nissan built in override. A LSD can be a viscous, or torsen or clutch type (three most popular). Torsen will send power to the wheel with the most traction, but if you have a wheel in the air it will freewheel like a open diff. Clutch will allow some spin on the wheel with the least traction but will always send some torque to the wheel with some traction. It's a simple 40% or similiar split in slippery situations. Viscous is like the torsen just less expensive and wears out fast.
Stock Pathfinders may have either a limited slip or open rear differential. How to determine this can be found by searching this forum. Stock Pathfinders have a lockable center differential, except for some fancier newer ones with the All-Mode system, which amounts to a limited slip/lockable center differential.
Thanks for the replies. Curiosity got the better of me. I blocked the front wheels, jacked up the rear axle so the rear wheels spun freely, and found that turning one wheel produces counter-rotation of the opposite wheel. So, no LSD for me. Some further internet investigation tells me the feature was dropped in 2003 when the manual transmission was deleted as an option.
Could you further explain the "lockable center differential"? What does this do? What does it mean to me? My 2003 SE has every option EXCEPT VDC. As an SE, it does not have the All-Mode, but instead a shift-on-the-fly lever selection.
Last edited by MRMDFY : Oct 4th, 2005 at 12:06 AM.
Could you further explain the "lockable center differential"? What does this do? What does it mean to me? My 2003 SE has every option EXCEPT VDC. As an SE, it does not have the All-Mode, but instead a shift-on-the-fly lever selection.
The center differential is like the differential on an axle, except that the center differential is connected to the front and rear differentials. That's how the drivetrain gets power to the front wheels.
I'm surprised to hear a Pathfinder as new and fancy as yours has such a basic 4wd setup. In fact, I can't think of a 4wd system that's any simpler or limited. Even our '91 arguably has a better setup because we have a limited slip rear differential.
Your center differential, or transfer case, has three "states". One is that it is not engaged, and so your PF is plain old rear-wheel drive. This is 2H on the selector.
Without a locking or limited slip rear differential, you will have no propulsion if one rear wheel starts spinning.
The next state is if you lock the transfer case, in 4H. This means the front and rear drive systems are locked together. But it is still, in effect, an "open" differential. So if you end up spinning one wheel on each axle, you'll be going nowhere. A locking or limited slip rear differential will either prevent, or delay, that spinning and so maintain traction.
The third state is locked, in 4L. This means the transfer case is locked, and also is doing a gear reduction. So your normal 5 speed gearing is greatly reduced. I think the PF low gearing is a 50% reduction. The spinning wheel dynamics are the same as in 4H.
I believe the difference between your system and the All-Mode system is that in the All-Mode system, the transfer case is limited slip, and can be locked, shut off, or can engage itself by sensing wheel slippage. That means you can use it on dry pavement, and it takes a greater difference in traction between the axles before losing power to spinning wheels.
Hopefully now the people who really know this stuff will correct what I've said.
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'91 Pathfinder SE 5spd (now sold)
'06 Suzuki Grand Vitara JLX-L
Damn. Well, thanks for the info I guess. So All-Mode would have been an improvement. I chose the SE over the LE in part because I thought the manual transfer case selector would be a more direct/active system. So, without compromising on-road performance/longevity, what would you recommend to improve this system? What I'd ultimately like is something my wife can drive to work Monday through Friday, but won't leave us stuck in snow on the way up to the mountain. Also, as the Pathy ages (had it since it was brand new) I can see wanting to do some more liberal off-roading. I have the understanding that lockers will cause premature wear in a vehicle that sees mostly street driving. I'd like a cost-realistic solution to this "problem" that won't cause new problems in itself.
Damn. Well, thanks for the info I guess. So All-Mode would have been an improvement. I chose the SE over the LE in part because I thought the manual transfer case selector would be a more direct/active system. So, without compromising on-road performance/longevity, what would you recommend to improve this system? What I'd ultimately like is something my wife can drive to work Monday through Friday, but won't leave us stuck in snow on the way up to the mountain. Also, as the Pathy ages (had it since it was brand new) I can see wanting to do some more liberal off-roading. I have the understanding that lockers will cause premature wear in a vehicle that sees mostly street driving. I'd like a cost-realistic solution to this "problem" that won't cause new problems in itself.
Don't try and fix a problem that doesn't even exist. You should think about some good snow tires for snow. Other then that, if it's never left you stuck, what are you worried about.
More to the question. You can look into air lockers for the axles. They are open unless you activate them. Also, you may look for just a standard LSD of some sort. A full time rear lsd will make the truck more likely to swap ends in the snow so be carefull. Open diffs are really not so bad. Until you prove a need for more traction don't start throwing parts at the truck.
I can appreciate that. This is more in anticipation than anything else. I'm ready after an approximately three year hiatus to return to active snowboarding/snowskiing. I've really only been able to go a few times in the last three years since having the Pathfinder and the roads weren't so bad those times. Now that I'll be going nearly every weekend, I'd like to help ensure I won't have the day spoiled by being stranded on the side of the road (or worse). I just replaced the OE tires with some Nitto Terra Grappler All Terrain 255/55/18 tires. An air locker, eh? Okay.... That sounds like a good idea. Only engages when activated, so it doesn't interfere otherwise. I like it. ARB makes one for my truck, right? Is installation fairly straightforward and achievable with common garage tools? Is cost reasonable? Any alternative brands to consider?
I'm not sure what 98sr20ve meant by a limited slip rear differential making it easy to swap ends in snow. It's true that in 2wd, rear wheel drive, with a rear limited slip differential, that if you floor it on a slippery surface, you will spin both rear wheels rather than just one as would be the case with an open differential.
And if you spin both rear wheels while cornering, you're more likely to slide the back end out than with one rear wheel spinning. But... you can slide the back end out with either, it's just a matter of degree, and from my experience, not much degree. I've found this dynamic is absolutely predictable, no surprises with either setup. In a 2wd vehicle, climbing a steep slippery road with sharp corners, spinning the rear wheels to slide the rear end out is a good way to maintain your momentum around the corners. That's how cars are raced on ice, and rear wheel drives on gravel.
But then add 4wd into the equation. A basic 4wd with a limited slip rear differential is far lesss likely to get stuck than without the limited slip rear end. Like, if you have to diagonal through a ditch while climbing. Or if you have to start off uphill with either front wheel and either rear wheel lacking traction. Even on the same side, like if you park on an unplowed shoulder.
Pathfinders are so light in the back end that in 2wd mode, you can spin one rear wheel extremely easily. This strikes me as a major hazard on a road with patches of ice and bare pavement, where you can't use 4wd because you shouldn't engage it on bare pavement. The setup with the rear limited slip, in this same conditions, if you give it power with one rear wheel on ice and the other not, you won't spin either wheel. But you are at a bit more risk if you give it power with both rear wheels on ice.
In a way, you're lucky. You can convert an open rear differential to a locker, but you can't so convert a limited slip differential. Or that's what I understand from my research when I was thinking of buying an older QX4. So if you had a limited slip rear, and wanted a locking rear, you'd have to swap axles. To convert an open diff to a locker means changing some parts inside the differential. Much easier.
Someone makes rear differentials that are normally limited slip, but can be locked. However, I doubt they make one that would fit the Pathfinder. Sounds to me like your best bet is a rear locker.
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'91 Pathfinder SE 5spd (now sold)
'06 Suzuki Grand Vitara JLX-L
Last edited by X-Traction : Oct 9th, 2005 at 11:00 PM.
I'm not sure what 98sr20ve meant by a limited slip rear differential making it easy to swap ends in snow. It's true that in 2wd, rear wheel drive, with a rear limited slip differential, that if you floor it on a slippery surface, you will spin both rear wheels rather than just one as would be the case with an open differential.
And if you spin both rear wheels while cornering, you're more likely to slide the back end out than with one rear wheel spinning. But... you can slide the back end out with either, it's just a matter of degree, and from my experience, not much degree. I've found this dynamic is absolutely predictable, no surprises with either setup.
To most people that is not a good feeling. Having one wheel not spin is safer for the novice driver.
Linear Mode
