What are the benefits of locking your hubs manually? Does it make the front end "posi trac?" or something?
Even though this question is 5 years old, it seems that it was not fully answered.
Does it make the front end "posi trac?" or something?
The manual locking hubs don't turn the front end into a posi-trac (LSD). They act much like a transmission's clutch by connecting the rotating axle to the wheel so it can be powered.
The differential itself will determine if it's an open diff, an LSD, or a locker.
Whether auto-locking or manual, unlocking the axles lets the wheels spin independent of the axles while in 2WD mode, which helps save fuel by not forcing the front differential to be turned by the wheels.
What are the benefits of locking your hubs manually?
As
@KyTerra mentions, when you need to rock the vehicle, auto-locking hubs will disconnect when the vehicle's direction changes and then re-lock in the new direction. This adds a lot of unwanted wear on the locking mechanisms and could actually result in failure if you're applying too much power when they're trying to engage. This is where manual lockers are more favorable, since they stay engaged at all times until disengaged manually.
There are some who claim that manual lockers are stronger and some who claim that our auto-lockers are quite robust. I have no idea and therefore can't comment on any particular style or brand.