Okay... I think I understand.

I have Aisin's as well. I like the reduction of wear/tear on my drivetrain. During winter months I lock my Aisins and shift in/out of 4x4 as need with the ADD.

However, with ADD defeated, you have to lock/unlock your hubs each time you shift in/out? It sounds like running with hubs locked and ADD defeated causes wear/tear. Is that true?

Yes with ADD defeated and the Aisins locked, I would incur a bit more wear-n-tear. Although, I have a 2" body lift versus the popular ball-joint spacers so no radical CV angles to worry about. My 4WD operation has been hit and miss with ADD for the past couple years. It's a vacuum line or the reservoir or a relay or some other nickel and dime part that goes out when I need it to be 100%. So I'm dropping the weakest link. It's a tool and I'm trying to keep it simple. Brew <img src="/forums/images/graemlins/cheers.gif" alt="" />

All the ADD does is keep the front driveshaft from spinning (and ring a pinion in the differential and 4wd section of the transfer case as well) when in 2wd. The CV axle shafts always spin.

Switching to manual hubs allows everything to stop spinning when the hubs are locked and in 2wd.

Running with the hubs locked and the ADD still intact is just like the stock ADD setup.

Running with the hubs locked and the ADD disabled spins everything up front all the time, but in 2wd there is just no power going to the wheels. More of a gas mileage and minor vibration/noise issue than a wear issue.