Editing Locking differential (section)

==Types==

===Automatic lockers===
Automatic lockers lock and unlock automatically with no direct input from the driver. Some automatic locking differential designs ensure that engine power is always transmitted to both wheels, regardless of traction conditions, and will "unlock" only when one wheel is required to spin faster than the other during cornering. These would be more correctly termed automatic unlocking differentials, because their at-rest position is locked. They will never allow either wheel to spin slower than the [[differential carrier]] or axle as a whole, but will permit a wheel to be over-driven faster than the carrier speed. The most common example of this type would be the Detroit Locker, made by [[Eaton Corporation]], also known as the Detroit No-Spin, which replaces the entire differential carrier assembly. Others, sometimes referred to as [[lunchbox locker]]s, use the stock differential carrier and replace only the internal spider gears and shafts with interlocking plates. Both types of automatic lockers will allow for a degree of differential wheel speed while turning corners in conditions of equal traction, but will otherwise lock both axle shafts together when traction conditions demand it.
* Pros: Automatic action, no stopping for engagement or disengagement is necessary when road conditions change.
* Cons: Increased tire wear and noticeable impact on driving behaviour. During cornering, which half-axle is uncoupled is dependent on torque direction applied by the driveline.  When the torque direction is reversed, the speed of the driveline is suddenly forced to change from the inner to the outer axle, accompanied by tire chirping and a strong jerk. During cornering, the automatic locker is characterized by heavy understeer which transitions instantly to power oversteer when traction is exceeded.<ref>{{Cite web |date=2016-12-24 |title=How Auto Lockers Work |url=https://www.leisurewheels.co.za/blogs/auto-lockers-work/ |access-date=2021-11-22 |website=Leisure Wheels }}</ref>

Some other automatic lockers operate as an open differential until wheel slip is encountered and then they lock up. These types generally use an internal governor to monitor vehicle speed and wheel slip. An example of this is the Eaton automatic locking differential (ALD), or Eaton automatic differential lock (ADL), developed by the Eaton Corporation and introduced in 1973 for [[General Motors|GM]]'s Rounded-Line [[Chevrolet C/K#Third generation (1973–1991)|C/K Series]] pickups and utilities.<ref>{{cite web |title=1974 Chevy/GMC Pickups |url=http://www.73-87.com/7387info/articles/74pu02.jpg |website=73-87.com |access-date=2012-06-24 }}</ref> The Eaton ADL is sometimes incorrectly called the Gov-Lok, despite neither GM nor Eaton ever calling it by that name. Gov-Lok is rather an [[Neologism|unofficial name of unknown origin]] that gained popularity over the years. Both Eaton and GM do not know where the name came from, and Eaton has made several unsuccessful attempts in the past to debunk the Gov-Lok name.<ref>{{cite web |title=Randy's Ring & Pinion |url=http://www.thedieselpage.com/reviews/randys.htm |website=TheDieselPage.com |access-date=2012-05-24 }}</ref> An updated version of the old Eaton ADL design is still available from Eaton, now known as the Eaton mLocker mechanical differential lock.

Some other automatic lockers operate as an open differential until high torque is applied, at which point they lock up. This style generally uses internal gears systems with very high friction. An example of this is the ZF sliding pins and cams type available for use in early Volkswagens.

===Selectable lockers MRT===
[[File:10.5AAMram.JPG|thumb|Dodge Power Wagons feature front and rear selectable locking differentials]]

Selectable lockers allow the driver to lock and unlock the differential at will from the driver's seat. This can be accomplished in many ways. 
* Compressed air ([[pneumatics]]).  
* [[Automobile_accessory_power#Vacuum|Vacuum]]
* Cable-operated mechanism as is employed on the "Ox Locker".
* Electronic [[solenoid]]s and ([[electromagnet]]ics) like Eaton's "ELocker". However, OEMs are beginning to offer electronic lockers as well.  Nissan Corporation's electric locker can be found as optional equipment on the Frontier (Navara), Xterra, and Titan.  Ford offers an electronic rear locker on the F-series and Ranger trucks, as well as the fullsize Bronco.  Toyota currently offers a rear e-locker on the Tacoma, 4Runner, and Tundra (2022+) (TRD Off-Road and TRD Pro trims only), but has also offered front and rear e-lockers on vehicles such as the Land Cruiser in the past.
** Pros: Allows the differential to perform as an "open" differential for improved drivability and maneuverability, and provides full locking capability when it is desirable or needed.
** Cons: Mechanically complex with more parts to fail.  Some lockers require the vehicle to stop for engagement.  Needs human interaction and forward-thinking regarding upcoming terrain.  Unskilled drivers often put massive stress on driveline components when leaving the differential in locked operation on terrain not requiring a locker.

===Spool===
A spool or full spool (in contrast to mini-spool) is a device that connects the two axles directly to the ring gear. There is no differentiation side to side, so a vehicle equipped with a spool will bark tires in turns and may become unmanageable in wet or snowy weather. Spools are usually reserved for competition vehicles not driven on the street.<ref>{{cite web |title=Standard Carriers, Positraction & Limited Slips, Locking Differentials, Spools and Mini-Spools |url=http://www.ringpinion.com/TechnicalHelp/ContentFrame.aspx?FilePath=%7e%2fContent%2fParts%2fGeneralInfo%2f%2fStandard_Carriers%2c_Positraction_and_Limited_Slips%2c_Locking_Differentials%2c_Spools_and_Mini-Spools.inc |website=RingPinion.com |access-date=2012-08-29 }}</ref>

Mini-spool uses the stock carrier and replaces only the internal components of the differential, similar in installation to the lunchbox locker. A full spool replaces the entire carrier assembly with a single machined piece. A full spool is perhaps the strongest means of locking an axle, but has no ability to differentiate wheel speeds whatsoever, putting high stress on all affected driveline components.

The internal spider gears of an open differential can also be welded together to make a locked axle; this method is not recommended as the welding process seriously compromises the metallurgical composition of the welded components, and can lead to failure of the unit under stress.

====Welded differential====
Regular "open differential" with internal gears welded together to form a locked differential or spool. Common for [[Drifting (motorsport)|drifting]] or offroading where locking differentials are too expensive or unreliable.