open diff? closed diff? whats the dif?

[xj2fsj]

what are the differences in these two designs? pros and cons? reasons for a difference? I really haven't the faintest idea, and this seems to be one of those things that 4x4 mags and books assume everyone knows. so maybe it would behoove me to learn. BTW, if your'e not sure yourself please just check back later and read whats been posted by those in the know. Any guessing would only serve to confuse me smile.gif

p.s. what style does my 82 wag 44f/d20r have?

a moment of reflection for the tragic end of Layne Staley

[Crazy_Jeepman]

The Diff is what is in the front and rear axles, it Differentiates power to the right and left wheels from the driveshafts. Now an open Diff will send power to the wheel with the least amount of resistance. A Posi-trac or Lockers will provide power to both wheels at a determined amount of torque set by clutches, a spool will provide power to both wheels no matter what. There are a few other versions as well, however this is a basic idea as to the operation of open and locked Diffs. Hope that helps ;)

[Crazy_Jeepman]

<blockquote>quote:</font><hr>what style does my 82 wag 44f/d20r have? <hr></blockquote>
All front Diffs are open. Some rear diffs were trac-loc optional. However most rear axles are open as well. If your rig has the trac-loc option it would be most likely wore out and operate as an open diff. Trac-locs wore out very quickly.

[bchesley]

First off the term open diff is a little miss leading. The term is used to describe a differential that allows the wheels to turn in opposite directions with no resistance. What this means is that if one wheel looses traction the other will not spin thus resulting in being stuck. It does this because there are smaller gears in side that allow the wheels to spin at different speeds but both spinning in the same direction. This is of course the best set up for on road driving. This has the least about of drawbacks like excessive tire wear,and binding as you turn. The open diff is not the best for off road. The best for off road is a locker. This would be a closed diff in your terms. This means that the axles are locked together and spin at the same speed all the time. Some of the lockers release as you go around tight corners but can engage if you give it too much throttle. This is of course the best for off road because if one wheel gets off the ground or looses traction the other is still going to spin and move the vehicle forward. Some jeeps came with a tracloc which is a form of a locker but most come with an open. One way to check your vehicle is to jack up one of the rear tires and spin the wheel. If is spins with out any resistance it has an open.

[xj2fsj]

do they make traction enhancing devices for "winter weather,on road" driving? I hear that some lockers can make you lose control on ice. I do about 85% of my driving on streets including highway. this will probably change as I get more confidence in myself and my "reliable" FSJ. what is my best bet for winter wonderland a set-up? Remember "Minnesota"= snow and ice most of the year.

[Joe H.]

You could get the best of both worlds and get an ARB air locker, but they're expensive and require professional installation.

[porkchop]

<blockquote>quote:</font><hr>Originally posted by xj2fsj:
Remember "Minnesota"= snow and ice most of the year.<hr></blockquote>

I hear that! I am in Minnesota right now and it snowed last night. 4" in april. It has been awhile since I have seen that.

[Crazy_Jeepman]

For a daily driver and driveing on slippery roads you are better off with the open DIFFS ;)

[jeepbob]

Although if you are in a state that allows studded tires in the winter a posi is nice.

[xj2fsj]

thanks guys, I appreciate your time and experience. I just want to clear one thing up,when i asked "whats the dif?" I meant whats the difference not whats the differential. I was gonna let that go so as not to offend anyone but then my ego told me that I looked stupid...man I listen to that thing way too much smile.gif

[Bombadier]

Isn't that was what e-drive is for, to prevent wheelspinning? so you can kinda overcome the open diff running all the power to the spinning wheel. which is why you don't use it on high-traction surfaces, because of binding and tear on the driveline? just making sure i got it straight.....

[derf]

One thing to add, that was hinted at but not specifically stated was the difference between limited slip and lockers.

The limited slip differential, called Positrac by GM and TracLock by Jeep (Dana/Spicer actually), is just what the name implys. It only limits the slip of the wheel with no traction. It will apply only some of the power to the wheel with traction. This is the best for street driving, even on snow and ice since the two wheels are never quite locked together. The limited slip is better for off roading than an open differential but not as good as a locker.

The locker completely locks the wheels together, allowing no slip whatsoever. The wheel without traction will turn only at the rate that the wheel with traction spins, in effect sending 100% of the power to the wheel with traction. Lockers can "unlock" either automatically or manually, allowing different wheel speeds on road.

The spool on the other hand is just a solid piece connecting the two axle shafts together. It is 100% locked all the time. Not good for street driving (it's hard on axle shafts and tires) but great for off roading. A "Lincoln Locker" acts as a spool since it's just a normal differential with the spider gears welded together.

[ April 23, 2002: Message edited by: derf ]</p>

[bruno89]

Bombadier, The E-drive in a Qudra Trac only locks the differential in the transfer case. Since the center diff in the QT is a limited slip diff the e-drive locks this up to prevent wheel slip front to rear not side to side. The axle diffs are still open.

[Manhattan]

I would agree that open dif's or a limited slip in the rear is the best set-up for a primarily street driven vehicle - especially with a lot of snow.

I have a locker in the rear of my GW. It is like magic off-road. The leap in performance from open to locked was equal to that of shifting from 2 to 4-wheel drive. However, the GW is not my daily driver. On the road, it has some odd characteristics - it will fishtail with quick or heavy throttle if the street is wet. The inside tire chirps when I make a tight turn. I'll admit that I kind of like these little idiosyncacies - they make me think that I should be on the dirt... where the Jeep belongs!

[jode]

Quadra trac is not "4 wheel drive" until it is put in "E-drive". Here's why...
Quadra trac is set up ( as previously mentioned) so that it allows differentiation on the road between all four wheels...translation...if one wheel slips, all (most of it anyway)power is transferred to that wheel. That means that one driveline is not moving and the other is spinning with little resistance. Once the "E-drive"is engaged, it turns the QT into a "real" 4 -wheel drive where both front and rear axles get an equal amount of power and driveline rotation.
So that's the E-drive...in my opinion, youarent in true "4 wheel drive" intill the Edrive is engaged.
The next step is lockers which take the exact same concept a step further.
Essentially, "4 wheel drive" gives you 2 wheels (or more) turning at all times gauranteed. 4 wheel drive + 1 locker gives at least 3 wheels turning at all times and 4 wheel drive plus 2 lockers equals TRUE 4wheel drive where all four wheels get power and turn equally ALL of the time.
In fact, a normal "2 wheel drive" car (or a Jeep in the quadratrac mode) essentially is a 1 wheel drive.
Hope this helps...
It all makes sense in my head anyway.... smile.gif

[Shane]

Makes sense to me too!

[ April 23, 2002: Message edited by: Shane ]</p>

[WillyPete]

i've got my rearend lincoln locked and i love it :cool:

it makes offroad driving incredible; i can go places with my J10 and 30s that moderately lifted rigs with open diffs can't touch.

best $$$$ i ever spent, and it was about 1/10th of a detroit locker

my tires wear out a bit quicker tho redface.gif

[ April 24, 2002: Message edited by: WillyPete ]</p>