Having the rear locker has a few benefits.
Rear tires wear even, instead of the right rear tire showing the most wear. No I'm not talking about doing i wheel burn outs.
Having one also lessen the use of the front axle, less maintenance. Less tire cupping on the front tires.
Not turning all that extra drivetrain helps with fuel mileage.
You don't have the binding in the drivetrain when turning on to a dry patch of paved surface.
Thats a few, less maintenance, fuel, and tires are the main items.
- Rear locker doesn't affect front axle, as front is controlled by transfercase. Your tire cupping is caused by something else.
- T-reg is full-time AWD so it will turn all drivetrain was there RDL or not.
- On full turn, binding is caused by AWD and each wheel travelling different circle (radius) and by that, all 3 differentials are running different revolutions.
On AWD, rear locker is useless on normal drive and usefull on low range.
I had front and rear 100% lockers on my old MB G and activating 100% rear locker on normal drive during the winter is fastest way to get the tail come around...
I share the boat with Mountain and Nick on this topic.