It's been called the Lincoln Locker for decades, but not because ol' Honest Abe had one in his ride. 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-fusing device that you have plugged into the wall of your garage" locker. Now, before we get too far in the low-budget realm of welding your spider gears, we need to look at why one would even do such a thing.
The standard differential carrier in most vehicles is what's known as an open carrier. This is a series of (generally four) spider gears that rotate inside the carrier and are designed to delegate the power to your axleshafts. This design is sufficient for on-road purposes as it allows your tires to spin at different speeds, so when you corner and turn the vehicle there is less difficulty or bind. When you have an open carrier off-road it sends power to the tire with the least resistance, which usually means the tire with the least traction, leaving you a one-wheeled wonder.
By welding your spider gears solid, you have forced the shafts to rotate at the same speed, thereby creating a locker. Functioning similar to a spool, welding your spider gears is extremely hard on your equipment, but is without a doubt the cheapest and easiest locker you will never buy. It is great for off-road-only rigs, as you can have your rig locked up in less than an hour using only a drain pan, a can of brake clean, and a welder. So for all you guys wheeling on a budget, but who need traction now, here are a few steps to help get you on your way.
While people have been welding their spider gears for years, it's definitely something that comes with an inherent element of risk. Though lockers in general put more strain on your drivetrain components, a welded carrier can presumably cause even more internal damage if the welds break and the discarded pieces come between your bearings and ring-and-pinion. Street manners of a welded unit will be that of a spool-very aggressive-and may create strange handling. For our money, welding up your spider gears is a great way to get traction fast, especially if you're on a budget and you or your buddies have a welder handy.
Newly Opened Pulling the...
Newly Opened
Pulling the carrier out of the differential is more work, but sometimes worth it if your gas tank is nearby or your rearend is difficult to access. This also allows you to weld those tight and hard-to-reach spaces and keeps the slag out of your housing.
The basic "open" differential...
The basic "open" differential is comprised of a carrier, four spider gears, thrust washers, a center pin, and a lock pin. The two larger spider gears are splined for your rig's axleshafts to slide through and allow them to rotate at different speeds when uneven force is encountered by the tires. This makes it to where power travels down the path of least resistance. For example, if you had one tire planted on a rock and the other in the air, all the power would be sent to the tire in the air.
The first thing you'll need...
The first thing you'll need to do is grab an oil container and drain all of your differential fluid. For photographic purposes we plucked this Dana 44 rear axle out from under an old Jeep CJ, but traditionally you can weld your spider gears in the carrier while the axle is still under the truck.
Prepping the surface is extremely...
Prepping the surface is extremely important. This may require your blowing through an entire can of brake cleaner, but it's well worth it if you want the best welds. Be sure to thoroughly wipe down the axle for any remaining oil and grease that could catch fire.
The next step is to get your...
The next step is to get your welder adjusted to the proper settings. We MIG-welded ours using a Miller 210 with 0.30 wire and turned the heat up high. Welding cast and hardened steel is a bit tricky, so take your time and get your machine properly dialed in. Your target areas will be welding the carrier to the spider gears and the spider gears to each other. The idea is to have everything acting as one solid unit, very similar to a spool.