It's simply 4x slang for the type of machine used to weld your differential's spider gears in place. For all intents and purposes it could be a Hobart, Lincoln, Miller, or "whatever brand of metal ...

The spider gears should have smooth ... the spring pack is reinstalled along with the cross-shaft. Testing The Differential Using the method most builders use, check the action of the differential ...

To this point, the Locker acts just like a welded or solid spider gear differential, as there is no torque split or loss. Side gear tooth shape on the central driver is unusual, being what might ...

The mini-spool is an equally aggressive traction aid that simply takes the place of your open differential’s spider gears. Many modern 4x4 vehicles have what’s known as brake-bias traction ...

The work began by removing the differential’s center gears from its big, hefty iron housing. Disassembly then ensued, with the spider gears removed from their carrier and the other components ...

The differential turns the power 90° and sends ... The ring gear also spins a carrier containing perpendicularly meshing spider gears that allow the left and right axle shafts to spin independently.

The differential case itself (labeled "M," which includes the spider gears that turn the axles) gets spun by the planetary gear set's ring gear (labeled "K"). The aforementioned manual I found ...

How does a car's differential work ... still struggle to explain how that collection of ring, pinion, and spider gears gets power to the ground, and lets two wheels on the same axle spin at ...

It covers seven mechanisms: shafts, gears, cams, differentials, component solvers, integrators, and multipliers, and does so in the well-executed fashion typical of the era. Fire control systems ...