Editing Locking differential (section)

===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.