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jimmixj
12-22-2013, 09:53 AM
Posted this in another forum and realized someone might benefit. All info herein is experiential and subject to update/ revision. If I'm wrong about any or all of it, sorry!
A differential is designed to accommodate the difference in turning radius between two ends of an axle when going around corners. This works great when traction is not the primary concern but does allow power to be transferred to the non-tractive wheel. On the other end of the axle spectrum is the "live axle" which is solid from one end to the other, hence all power is transmitted to each end equally. This is an ideal setup where traction is the primary concern but sacrifices drivability.
There are various means of addressing this issue, but they fall into 3 basic categories; Limited Slip, Lockers and spools. A spool is a simple device that eliminates the differential altogether thereby locking the 2 axles together in phase, creating a live axle. This is also the end result of a "Lincoln Locker"; by welding the differential spiders you have locked the axles in phase and eliminated the differential action. Advantage: awesome power transfer to both wheels equally. Disadvantage: Drivability suffers greatly and LOTS of wear points; tires first, then axles, drivelines, etc. One important note; a live front axle WILL try to drive you wherever it is pointed.
Next are the Limited Slip and Locker type differentials; as the name implies these are both differentials so they do allow varying wheel speed during cornering but are designed to keep the axles close to phase in straight-ahead situations. They both accomplish this by making use of driven versus coasting (or positive vs negative) torque. When torque is being applied thru the driveshaft they both try to "engage" the axles equally; the difference is in the mechanism.
A Limited Slip uses a clutch pack or some other arrangement of friction material and spring tension to cause the spinning axle to "pull" the non-spinning axle along with it, hopefully pulling your Jeep out of that mess. They are smooth in engagement so parts breakage is less and they are very streetable, but friction material tends to wear (think brakes and clutches) so there is a cost associated with that. In addition, it's possible to "smoke" the clutch pack in a really stuck situation...
Lockers, on the other hand, use a mechanical action to lock the axles in phase. This is true whether the locker is passive or active (switchable) and results in a "live axle" when locked. Hence, they tend to be better at more aggressive wheeling but at the cost of streetability, at least in the case of passive lockers.
Making a decision about how to build a diff for an off-road vehicle does involve more than just which will give me the ability to climb the "Flipper". Drivability and durability are always paramount for me, so I went with the LSD in the rear and will eventually go to a passive locker in front.
Keep on wheelin!:bacondance:

editedforsafety
12-31-2013, 05:07 PM
A live axle is a beam style solid axle that has power. So, our xj's have live axles front and rear, regardless of whether they are open or locked.

4.3LXJ
12-31-2013, 05:14 PM
Yes

jimmixj
01-01-2014, 09:44 AM
A live axle is a beam style solid axle that has power. So, our xj's have live axles front and rear, regardless of whether they are open or locked.

True, in current terminology. What I was referring to is not the axle HOUSING but the axle itself. Live axle is the term that was used to describe an axle that was solid from one side to the other, like a go-kart, Model T (and other old cars) and used today in quads. Sorry for any confusion.

cantab27
01-01-2014, 12:59 PM
tis the basics to a good 4wd.........IFS is for comfort when driving on the black stuff in ya soccer mummys suv......mmmmmm soccer mums ...

4.3LXJ
01-01-2014, 07:10 PM
tis the basics to a good 4wd.........IFS is for comfort when driving on the black stuff in ya soccer mummys suv......mmmmmm soccer mums ...

And tailgate parties :rolleye0012:

GoneWithTheWind
09-20-2015, 06:34 PM
Earlier I was looking for a way to identify my differentials. Here is a link for front and rear differentials, and how to tell them apart. http://www.fourwheeler.com/how-to/transmission-drivetrain/154-1109-jeep-cherokee-axle-guide/
I hope this helps someone else as much as it helped me.