sorry I should have explained a little bit more for the question; currently its a 2006 LX470 with a locking differential. A-Trac and all. For my current stuff it works great. I work in the healthcare industry so I have to go out in all sorts of weather because I live in the northeast part of the country. I currently do some beach stuff which the vehicle has never let me down but that I think was me being conservative on where I go. Planing a trip this summer which will include Utah, death valley, and some other nation parks where I will HAVE to take a certain route. So the vehicle has to get thru. I know many other have broken the front diff when hard use; so going with an ARB front locker is a preventive prep for the trip.
Now with regard to the vehicle locking the diff now gives me a one wheel drive system ( meaning all four wheels are moving); going with the front locker I will get a 2 wheel system now. Front and rear correct?? My question to all is; the factory rear locker is ok and does not need upgrading??? Or am I all messed up which this idea and don't need to touch anything?
I'm not sure you fully understand the mechanics of the 4wd system. Let's clear a few basic things up:
I believe when you are referring to the factory locking differential, you are referring to the CENTER diff lock (4x4) button. This puts the vehicle in true 4wd. Locking the CENTER diff does not affect the rear or front diffs, they are still open / open. Locking the center diff equally splits the power to the front and rear drive shafts. Power will be transferred to the all 4 wheels, with a strong preference to the wheel with less traction on each axle. This is why you see one wheel spinning in low / loose traction situations, or the wheel that is in the air spinning in crossed up positions. Power is being directed through the diff (front or rear) to the wheel with the least resistance. Obviously this is not what we want when off road. (Side Note: A-trac mimics a Limited Slip Diff or locker by sensing wheel spin. By applying break pressure to the spinning wheel, it will push power to the wheel on the axle with weight = traction. Because of the way it works, it takes some time and wheel spin for the system to kick in. ) A FRONT or REAR locker, when engaged, will always put equal power to both wheels on the axle, regardless of weight distribution or traction. This is a huge help when one wheel is in the hanging in the air or on loose surfaces.
A front locker will not prevent damage to the front diff. It is more likely to cause damage, especially if you are not sure when and how to use it correctly.
If you actually have a factory rear locker, you will be fine. I've done quite a few trips to Death Valley and driven many of the trails there. I only used my rear locker a handful of times. Many times I could have done it without the locker, but with a little more work, but the locker is like an Easy Button. You will most likely be able to pass most trails in DV with 4lo and A-Trac.
Hope this helps.