[MrBeast]

a "Lincoln Locker" or welded diff is as mentioned previously when you weld the spider gears. Its a poor man's posi, and in my opinion it is a bad idea. Trucks have differentials for a reason. Locking up your axles will give you traction, but it will also be really hard on your axle shafts and tires it will tear up your equipment way faster because it is always going to be under a lot of stress.

If your rig is a trail only rig, you can get away with it, you really would be best off spending the few bucks and getting a locker.